Information

Health benefits & enzymes different between Thermophilic and Mesophilic Probiotic cultures?

Health benefits & enzymes different between Thermophilic and Mesophilic Probiotic cultures?



We are searching data for your request:

Forums and discussions:
Manuals and reference books:
Data from registers:
Wait the end of the search in all databases.
Upon completion, a link will appear to access the found materials.

Is there a difference between the Enzymes produced by Thermophilic vs Mesophilic Probiotic cultures ? are there any other differences in health benefits between the two types of cultures ?


Thermophilic and mesophilic enzymes differ in the optimal working temperature, due to a structural adaptation: thermophilic enzymes have more stiff surface-exposed loops than their mesophilic orthologs. Human is mesophile, which means that mesophilic enzymes, no matter whether human or bacterial, will work in human more efficiently.


Bjelic, Brandsdal, and Aqvist (2008) Cold adaptation of enzyme reaction rates. Biochemistry 47: 10049-10057; emphasis mine:

[P]sychrophilic, mesophilic, and hyperthermophilic citrate synthases… have increasingly stronger electrostatic stabilization of the transition state, while the energetic penalty in terms of internal protein interactions follows the reverse order with the cold-adapted enzyme having the most favorable energy term. The lower activation enthalpy and more negative activation entropy observed for cold-adapted enzymes are found to be associated with a decreased protein stiffness. The origin of this effect is, however, not localized to the active site but to other regions of the protein structure.

https://www.ncbi.nlm.nih.gov/pubmed/18759500


Aqvist (2017) Cold adaptation of triosephosphate isomerase. Biochemistry 56: 4169-4176; emphasis mine:

The results show that the enzyme from the psychrophilic bacterium Vibrio marinus indeed displays the characteristic shift in enthalpy-entropy balance, compared to that of the yeast ortholog. The origin of this effect is found to be located in a few surface-exposed protein loops that show differential mobilities in the two enzymes. Key mutations render these loops more mobile in the cold-adapted triosephosphate isomerase, which explains both the reduced activation enthalpy contribution from the protein surface and the lower thermostability.

https://www.ncbi.nlm.nih.gov/pubmed/28731682


What’s The Difference? Fermentation vs Pickling

Fermentation and pickling can be easy to mix up there are some areas of overlap that can easily spark some confusion.
After all, you can make fermented cucumber pickles, or pickled cucumber pickles. But, do fermented cucumber pickles qualify as fermented, or pickled? For the answers to this question and more, read on as we explore the overlap between these two methods of food preservation and preparation.
In short, here&rsquos what you need to remember: Pickling involves soaking foods in an acidic liquid to achieve a sour flavor and fermentation generates a sour flavor as a result of a chemical reaction between a food&rsquos sugars and naturally present bacteria &mdash no added acid required.

Pickled and Fermented, defined in detail

  • Pickling - A pickled food has been preserved in a brine of equal parts acid and water mixed with salt. The brine can be salt or salty water, and the acid is often vinegar or an acidic juice like lemon juice. Pickled foods that are not fermented do not offer the probiotic and enzymatic benefits of fermented foods because they are usually heated for sterilization and preservation purposes during canning. However, when heated and canned, pickled foods can be stored at room temperature much longer than fermented food..
  • Fermenting - A fermented food has been preserved by bacteria. One of the most common kinds of bacteria is Lactobacillus, a bacteria that eats the natural sugars and carbs and produces (among other things) lactic acid. This lactic acid preserves the food and adds to its flavor. Home fermented foods contain probiotics and enzymes that offer health and digestion benefits. These foods should be refrigerated or kept in a cool place like a root cellar.

Overlap between the two

While some pickles are fermented and some fermented food is pickled, not all pickles are fermented and not all fermented foods are pickled. It sounds confusing, but becomes clearer when we consider some examples.

  • Fermented, not pickled - Yogurt, sourdough bread, beer, kefir, cheese, kombucha, and sour cream are all fermented foods that are not pickled. They are not preserved in an acidic medium, and the fermentation process does not generate enough acid to qualify them as pickled. These are mostly easy examples, as you wouldn&rsquot look at a loaf of sourdough bread and think that it had been pickled. But, if you&rsquore not familiar with kombucha, a fermented tea, you might wonder. It&rsquos a liquid, but not salty, and it can develop a vinegar taste if left to ferment for an extended period of time. The answer? It&rsquos a fermented food. The vinegar taste is created by bacteria in the SCOBY eating the sugars in the tea. On a side note, this 2 Gallon Keg and Spigot is great for fermenting and continuous brewing of kombucha teas. Visit our website for more information on all things kombucha.
  • Pickled, not fermented - Store-bought pickles or anything that&rsquos been quick-pickled is not a fermented food. These are a little harder than the last category to identify, but they do lack the distinctive flavor of a fermented food. If this is something you&rsquore interested in, our ultimate canning kit for pickling and canning non-fermented foods has you covered.
  • Both - Some foods are both pickled and fermented. Foods like sauerkraut, fermented pickles, and kimchi fall into this category. Surströmming, or Swedish sour herring, is both pickled and then fermented. In each of these foods, they are placed in a salty brine that kills off harmful bacteria, thereby pickling the food. The benign bacteria then goes to work fermenting the food, resulting in a fermented and pickled food. If you&rsquore interested in fermenting your own food, this fermenting kit has everything you need to get started.

Notable Differences between Fermenting and Pickling

Temperature

We&rsquoll start with fermented foods. All fermented foods depend on bacteria to change their state, improve their flavor, and preserve them for later consumption. These bacteria thrive at certain temperatures, and depending on whether you&rsquore using a mesophilic or thermophilic cultures, can die off if they get too hot. Mesophilic bacteria thrive between 68℉ and 113℉ and thermophilic bacteria thrive between 106℉ and 252℉. That&rsquos why this electric yogurt maker is so helpful during the yogurt-making process. It keeps the milk at a constant preset temperature during the fermentation process. Some fermented foods, (like sourdough bread during the baking process,) use heat as part of the recipe to kill the bacteria. But in other fermented foods like kimchi, sauerkraut, or even fermented pickles, the bacteria and enzymes live on, only going dormant when the food is chilled or refrigerated. In fact, these foods must be stored below 45℉ and preferably refrigerated.
Pickled foods are much less temperature sensitive. They are often canned, which means they are heated to boiling and kept there for a set amount of time. This process would kill a mesophilic bacteria, but it also means these pickled foods are shelf-stable at room temperature.

Desired Result

Why choose pickling over fermenting or vice versa? Pickling creates food that can be stored for longer periods of time at room temperature. Fermenting can create a wider variety of foods, with more health benefits that contain like enzymes and probiotics, but most will require refrigeration and last for six months to a year at most, although some things like kombucha never expire. For more information about homemade fermentation, try Homemade Fermentation by Mortier Pilon, and for more pickling ideas, try our Favorite Pickles and Relish Book.


Chapter 8 - Bacterial and Yeast Cultures – Process Characteristics, Products, and Applications

This chapter reviews bacterial and yeast cultures, their fermentation products and process characteristics, and challenges in large-scale fermentation for production of industrial bio-based products from renewable resources. It describes several factors, such as cell characteristics, cell culture and fermentation processes, determining a successful and economical production. Bacteria and yeast transform sugars from renewable resources into a variety of value-added chemicals, solvents, and fuels as alternatives to petroleum-based chemicals. Bacterial and yeast fermentations have provided sustainable, cost-competitive, and biocompatible products from renewable resources. Scientists have engineered bacterial genes to improve the production of value-added substances, such as fine chemicals, biodegradable plastics, bio-fuels, and vitamins. The difficulties in converting biomass to desired products have been ameliorated by genetic manipulation. Metabolic engineering has been applied to improve and change the existing metabolic activities of several bacteria and yeasts for the production of industrial chemicals. These tools have enhanced utilization of biomass and reduced the cost of bioprocesses. The chapter lists some important fermentation products, including alcohols, biofuels, bio-polymers, bio-surfactants, specialty chemicals, materials, polysaccharides, enzymes, and vitamins.


INTERACTIONS BETWEEN PROBIOTICS AND COMPONENTS OF FERMENTED FOODS

Besides their desired health and clinical properties, probiotics must meet several basic requirements for the development of marketable probiotic products. The most important requirements are that probiotic bacteria survive in sufficient numbers in the product, that their physical and genetic stability during storage of the product be guaranteed, and that all of their properties essential for expressing their health benefits after consumption be maintained during manufacture and storage of the product. In addition, probiotics should not have adverse effects on the taste or aroma of the product and should not enhance acidification during the shelf life of the product. Finally, methods should be available to identify probiotic strains unequivocally.

To fully exploit the functional properties of probiotic bacteria, the processes used to manufacture dairy products must be modified to meet the requirements of the probiotics. When this is not possible, other probiotic strains must be tested or, in extreme case, new products must be developed. In this section, I address some of the variables necessary for or influencing the application of probiotics in dairy products.

As with all fermented dairy products containing living bacteria, probiotic products must be cooled during storage. This is necessary both to guarantee high survival rates of the probiotic organisms and to ensure sufficient stability of the product ( 12, 13). Furthermore, because the intestinal tract is considered to be the natural environment of the probiotic bacteria, the oxygen content, redox potential, and water activity of the medium must be considered ( 14).

Active microorganisms interact intensively with their environment by exchanging components of the medium for metabolic products. Thus, the chemical composition of the dairy product is of paramount importance for the metabolic activities of the microorganisms. Essential variables are the kind and amount of carbohydrates available, the degree of hydrolysis of milk proteins (which determines the availability of essential amino acids), and the composition and degree of hydrolysis of milk lipids (which determine the availability of short-chain fatty acids in particular) ( 15, 16). On the other hand, the proteolytic ( 17) and lipolytic properties of probiotics may be important for further degradation of proteins and lipids. These 2 properties may have considerable effects on the taste and flavor of dairy products ( 15).

A major aspect of the production of probiotic fermented dairy products is the interaction between probiotics and starter organisms. Although little is known about this interaction, both synergistic and antagonistic effects between different starter organisms are well established. For example, the classic yogurt culture is characterized by a protosymbiosis between Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus. This synergism, seen as an accelerated and efficient acidification of the milk and multiplication of the culture organisms and based on cross-feeding of both organisms, is not a property of the 2 species but of specific strains of theses species ( 18– 21). Antagonism, on the other hand, is often based on the production of substances that inhibit or inactivate more or less specifically other related starter organisms or even unrelated bacteria. Most importantly, antagonism is caused by bacteriocins, which are peptides or proteins exhibiting antibiotic properties ( 22, 23). The ability to produce bacteriocins is often discussed as a desirable property of probiotics ( 10) however, antagonism to starter cultures and vice versa may be a limiting factor for combinations of starters and probiotics ( 24). Further antagonistic activities produced by lactic acid bacteria have been described and the substances involved are hydrogen peroxide, benzoic acid (produced from the minor milk constituent hippuric acid), biogenic amines (formed by decarboxylation of amino acids), and lactic acid ( 25– 29). An overview of the starter bacteria used in dairy fermentations and some of their relevant physiologic properties is given in Table 1.

Starter organisms for dairy products

. Growth temperature . Lactic acid fermentation . . .
Species 1 . Minimum . Optimal . Maximum . Homofermentative . Heterofermatative . Lactic acid . Final pH .
°C %
Lb. delbrueckii subsp. bulgaricus22 45 52 + 1.5–1.8 3.8
Lb. delbrueckii subsp. lactis18 40 50 + 1.5–1.8 3.8
Lb. helveticus22 42 54 + 1.5–2.2 3.8
Lb. acidophilus27 37 48 + 0.3–1.9 4.2
Lb. kefir8 32 43 + 1.2–1.5
Lb. brevis8 30 42 + 1.2–1.5
Lb. casei subsp. casei 30 + 1.2–1.5
S. thermophilus22 40 52 + 0.6–0.8 4.5
Lc. lactis subsp. lactis8 30 40 + 0.5–0.7 4.6
Lc. lactis subsp. cremoris8 22 37 + 0.5–0.7 4.6
Lc. lactis subsp. lactis biovar. diacetylactis8 22–28 40 + 0.5–0.7 4.6
Ln. mesenteroides subsp. cremoris4 20–28 37 + 0.1–0.2 5.6
Ln. mesenteroides subsp. dextranicum4 20–28 37 + 0.1–0.2 5.6
Bifidobacterium (bifidum, infantis, etc) 22 37 48 0.1–1.4 4.5
. Growth temperature . Lactic acid fermentation . . .
Species 1 . Minimum . Optimal . Maximum . Homofermentative . Heterofermatative . Lactic acid . Final pH .
°C %
Lb. delbrueckii subsp. bulgaricus22 45 52 + 1.5–1.8 3.8
Lb. delbrueckii subsp. lactis18 40 50 + 1.5–1.8 3.8
Lb. helveticus22 42 54 + 1.5–2.2 3.8
Lb. acidophilus27 37 48 + 0.3–1.9 4.2
Lb. kefir8 32 43 + 1.2–1.5
Lb. brevis8 30 42 + 1.2–1.5
Lb. casei subsp. casei 30 + 1.2–1.5
S. thermophilus22 40 52 + 0.6–0.8 4.5
Lc. lactis subsp. lactis8 30 40 + 0.5–0.7 4.6
Lc. lactis subsp. cremoris8 22 37 + 0.5–0.7 4.6
Lc. lactis subsp. lactis biovar. diacetylactis8 22–28 40 + 0.5–0.7 4.6
Ln. mesenteroides subsp. cremoris4 20–28 37 + 0.1–0.2 5.6
Ln. mesenteroides subsp. dextranicum4 20–28 37 + 0.1–0.2 5.6
Bifidobacterium (bifidum, infantis, etc) 22 37 48 0.1–1.4 4.5

Lb., Lactobacillus S., Streptococcus Lc., Lactococcus Ln., Leuconostoc.


Results and discussion

Reactor performance

Hydrogen consumption, methane yield, and VFAs

Summary of reactor performances

Stages . a d . b e . c f . d g .
Methane yield (L/kgVS) a
M b 197 ± 8 200 ± 16 245 ± 9 210 ± 13
T c 222 ± 8 242 ± 19 245 ± 19 245 ± 27
H2 consumption (L/day)
M 0 0.9 ± 0.1 1.1 ± 0.4 1.9 ± 0.7
T 0 1.9 ± 0.1 4.6 ± 0.5 6.4 ± 0.5
Relative methane content (%)
M 62 ± 0.4 65 ± 1 66 ± 0.8 70 ± 1.1
T 66 ± 0.6 68 ± 0.7 71 ± 1.3 78 ± 1.7
pH
M 7.36 ± 0.01 7.40 ± 0.03 7.63 ± 0.04 7.59 ± 0.04
T 7.63 ± 0.03 7.64 ± 0.07 7.89 ± 0.07 7.77 ± 0.06
BA (mg/L CaCO3)
M 6897 ± 1491 6976 ± 1708 4725 ± 1190 3055 ± 1189
T 8401 ± 990 11,490 ± 751 10,735 ± 565 10,937 ± 855
Total VFAs (mg/L)
M 1804 ± 119 1823 ± 142 1865 ± 94 2027 ± 210
T 3317 ± 326 2489 ± 136 2418 ± 284 2259 ± 252
Acetate (mg/L)
M 986 ± 98 998 ± 94 1023 ± 44 1266 ± 169
T 1736 ± 71 1155 ± 77 1081 ± 200 991 ± 93
Propionate (mg/L)
M 429 ± 30 413 ± 47 448 ± 60 357 ± 32
T 990 ± 74 848 ± 62 859 ± 126 856 ± 170
Ammonia nitrogen (mg/L)
M 1174 ± 36 1221 ± 82 1349 ± 82 1325 ± 60
T 1568 ± 46 1608 ± 69 1619 ± 79 1539 ± 221
Stages . a d . b e . c f . d g .
Methane yield (L/kgVS) a
M b 197 ± 8 200 ± 16 245 ± 9 210 ± 13
T c 222 ± 8 242 ± 19 245 ± 19 245 ± 27
H2 consumption (L/day)
M 0 0.9 ± 0.1 1.1 ± 0.4 1.9 ± 0.7
T 0 1.9 ± 0.1 4.6 ± 0.5 6.4 ± 0.5
Relative methane content (%)
M 62 ± 0.4 65 ± 1 66 ± 0.8 70 ± 1.1
T 66 ± 0.6 68 ± 0.7 71 ± 1.3 78 ± 1.7
pH
M 7.36 ± 0.01 7.40 ± 0.03 7.63 ± 0.04 7.59 ± 0.04
T 7.63 ± 0.03 7.64 ± 0.07 7.89 ± 0.07 7.77 ± 0.06
BA (mg/L CaCO3)
M 6897 ± 1491 6976 ± 1708 4725 ± 1190 3055 ± 1189
T 8401 ± 990 11,490 ± 751 10,735 ± 565 10,937 ± 855
Total VFAs (mg/L)
M 1804 ± 119 1823 ± 142 1865 ± 94 2027 ± 210
T 3317 ± 326 2489 ± 136 2418 ± 284 2259 ± 252
Acetate (mg/L)
M 986 ± 98 998 ± 94 1023 ± 44 1266 ± 169
T 1736 ± 71 1155 ± 77 1081 ± 200 991 ± 93
Propionate (mg/L)
M 429 ± 30 413 ± 47 448 ± 60 357 ± 32
T 990 ± 74 848 ± 62 859 ± 126 856 ± 170
Ammonia nitrogen (mg/L)
M 1174 ± 36 1221 ± 82 1349 ± 82 1325 ± 60
T 1568 ± 46 1608 ± 69 1619 ± 79 1539 ± 221

a Methane yield was determined at room temperature and 1 atm

d Intermittent mixing without H2 addition

e Intermittent mixing with less H2 addition

f Intermittent mixing with more H2 addition

g Continuous mixing with more H2 addition

Summary of reactor performances

Stages . a d . b e . c f . d g .
Methane yield (L/kgVS) a
M b 197 ± 8 200 ± 16 245 ± 9 210 ± 13
T c 222 ± 8 242 ± 19 245 ± 19 245 ± 27
H2 consumption (L/day)
M 0 0.9 ± 0.1 1.1 ± 0.4 1.9 ± 0.7
T 0 1.9 ± 0.1 4.6 ± 0.5 6.4 ± 0.5
Relative methane content (%)
M 62 ± 0.4 65 ± 1 66 ± 0.8 70 ± 1.1
T 66 ± 0.6 68 ± 0.7 71 ± 1.3 78 ± 1.7
pH
M 7.36 ± 0.01 7.40 ± 0.03 7.63 ± 0.04 7.59 ± 0.04
T 7.63 ± 0.03 7.64 ± 0.07 7.89 ± 0.07 7.77 ± 0.06
BA (mg/L CaCO3)
M 6897 ± 1491 6976 ± 1708 4725 ± 1190 3055 ± 1189
T 8401 ± 990 11,490 ± 751 10,735 ± 565 10,937 ± 855
Total VFAs (mg/L)
M 1804 ± 119 1823 ± 142 1865 ± 94 2027 ± 210
T 3317 ± 326 2489 ± 136 2418 ± 284 2259 ± 252
Acetate (mg/L)
M 986 ± 98 998 ± 94 1023 ± 44 1266 ± 169
T 1736 ± 71 1155 ± 77 1081 ± 200 991 ± 93
Propionate (mg/L)
M 429 ± 30 413 ± 47 448 ± 60 357 ± 32
T 990 ± 74 848 ± 62 859 ± 126 856 ± 170
Ammonia nitrogen (mg/L)
M 1174 ± 36 1221 ± 82 1349 ± 82 1325 ± 60
T 1568 ± 46 1608 ± 69 1619 ± 79 1539 ± 221
Stages . a d . b e . c f . d g .
Methane yield (L/kgVS) a
M b 197 ± 8 200 ± 16 245 ± 9 210 ± 13
T c 222 ± 8 242 ± 19 245 ± 19 245 ± 27
H2 consumption (L/day)
M 0 0.9 ± 0.1 1.1 ± 0.4 1.9 ± 0.7
T 0 1.9 ± 0.1 4.6 ± 0.5 6.4 ± 0.5
Relative methane content (%)
M 62 ± 0.4 65 ± 1 66 ± 0.8 70 ± 1.1
T 66 ± 0.6 68 ± 0.7 71 ± 1.3 78 ± 1.7
pH
M 7.36 ± 0.01 7.40 ± 0.03 7.63 ± 0.04 7.59 ± 0.04
T 7.63 ± 0.03 7.64 ± 0.07 7.89 ± 0.07 7.77 ± 0.06
BA (mg/L CaCO3)
M 6897 ± 1491 6976 ± 1708 4725 ± 1190 3055 ± 1189
T 8401 ± 990 11,490 ± 751 10,735 ± 565 10,937 ± 855
Total VFAs (mg/L)
M 1804 ± 119 1823 ± 142 1865 ± 94 2027 ± 210
T 3317 ± 326 2489 ± 136 2418 ± 284 2259 ± 252
Acetate (mg/L)
M 986 ± 98 998 ± 94 1023 ± 44 1266 ± 169
T 1736 ± 71 1155 ± 77 1081 ± 200 991 ± 93
Propionate (mg/L)
M 429 ± 30 413 ± 47 448 ± 60 357 ± 32
T 990 ± 74 848 ± 62 859 ± 126 856 ± 170
Ammonia nitrogen (mg/L)
M 1174 ± 36 1221 ± 82 1349 ± 82 1325 ± 60
T 1568 ± 46 1608 ± 69 1619 ± 79 1539 ± 221

a Methane yield was determined at room temperature and 1 atm

d Intermittent mixing without H2 addition

e Intermittent mixing with less H2 addition

f Intermittent mixing with more H2 addition

g Continuous mixing with more H2 addition

Hydrogen consumption under a mesophilic condition and b thermophilic condition

Hydrogen consumption under a mesophilic condition and b thermophilic condition

The increase in H2 partial pressure owing to H2 addition may inhibit the degradation of VFAs during actogenesis. In this study, under mesophilic condition, total VFAs stabilized to approximately 1800 mg/L in the first three stages yet increased to 2026 mg/L in stage d. Under thermophilic condition, after the H2 addition, total VFAs decreased by 28% compared with the starting stage, and was maintained at approximately 2400 mg/L in the last three stages. Thus, it can be concluded that the increase in pH mainly resulted from the inhibition of hydrolytic and fermentative bacteria by the added H2 [ 12]. The change in the tendency of acetate is consistent with that of total VFAs.

PH, BA, and ammonia nitrogen

The behavior of pH under mesophilic and thermophilic conditions changed in a similar way, but BA and ammonia nitrogen were inconsistent (Table 2). It was found that pH did not change after entering stage b, yet increased significantly in stage c, and then started decreasing when continuous stirring was adopted in stage d. Under mesophilic condition, the increase in ammonia nitrogen and CO2 consumption in the liquid phase resulted in pH increase in the Mc stage, whereas the increase of VFAs in the last stage induced pH decrease. Under thermophilic condition, the decrease in VFAs led to the increase in pH in the Tc stage, and the decrease in ammonia nitrogen caused the decrease in pH in the Td stage. Compared with the maximum pH value of 7.7 in the Mc stage, the pH reached the maximum value of 8.1 in the Tc stage. The BA, as the main buffer substance to maintain suitable pH, was increased and kept in a more stable state after H2 addition in the thermophilic reactor. Overall, the thermophilic condition showed a better performance with higher methane production compared with the mesophilic condition, except in stage c.

Comparison of mesophilic versus thermophilic reactors on microbial community composition

Overall microbial diversity

A total of 1,086,890-paired sequences with average length of 396 bp were generated from triplicate samples at eight different stages (Ta/Ma, Tb/Mb, Tc/Mc, and Td/Md). For this research, 97% OTU similarity threshold was set to conduct taxonomic analysis. Table 3 lists the alpha diversity index. H2 addition decreased the community diversity in the mesophilic reactor in the Mb and Mc stages, but the community diversity recovered in the Md stage. The added H2 had no significant effect on community richness. Compared with the Ma stage, both community diversity and richness were higher in the Ta stage. From the Simpson Even Index, the addition of H2 had no obvious effect under mesophilic condition. Compared with the Ta stage, more even distribution of microbial species was observed in the Tb stage, which decreased in the subsequent stages.

Summary of alpha diversity index

Alpha diversity index stages . a . b . c . d .
Simpson a
M 0.07 0.09 0.1 0.07
T 0.05 0.04 0.07 0.08
Chao b
M 745.6 762.1 741.1 735.4
T 797 714.3 671.2 719.4
Simpsoneven c
M 0.03 0.02 0.02 0.03
T 0.04 0.05 0.03 0.03
Alpha diversity index stages . a . b . c . d .
Simpson a
M 0.07 0.09 0.1 0.07
T 0.05 0.04 0.07 0.08
Chao b
M 745.6 762.1 741.1 735.4
T 797 714.3 671.2 719.4
Simpsoneven c
M 0.03 0.02 0.02 0.03
T 0.04 0.05 0.03 0.03

a The diversity of the microbial community

b The richness of microbial species

c The distribution evenness of the microbial community

Summary of alpha diversity index

Alpha diversity index stages . a . b . c . d .
Simpson a
M 0.07 0.09 0.1 0.07
T 0.05 0.04 0.07 0.08
Chao b
M 745.6 762.1 741.1 735.4
T 797 714.3 671.2 719.4
Simpsoneven c
M 0.03 0.02 0.02 0.03
T 0.04 0.05 0.03 0.03
Alpha diversity index stages . a . b . c . d .
Simpson a
M 0.07 0.09 0.1 0.07
T 0.05 0.04 0.07 0.08
Chao b
M 745.6 762.1 741.1 735.4
T 797 714.3 671.2 719.4
Simpsoneven c
M 0.03 0.02 0.02 0.03
T 0.04 0.05 0.03 0.03

a The diversity of the microbial community

b The richness of microbial species

c The distribution evenness of the microbial community

Beta diversity with Bray–Curtis dissimilarity: mesophilic reactor (ad) and thermophilic reactor (ad) are all triplicate samples

Beta diversity with Bray–Curtis dissimilarity: mesophilic reactor (ad) and thermophilic reactor (ad) are all triplicate samples

For thermophilic system, the remarkable increase of hydrogen consumption did not promote the methane yield from Tb to Td stages (Table 2), but it significantly changed the microbial composition (Fig. 2). This could indicate that the added hydrogen was mainly utilized for microbial cell growth via Wood–Ljungdahl pathway other than methane production [ 28]. The enhanced cell growth reformed steady anaerobic microbial system to resist the change of operational condition such as mixing mode. On the other hand, under mesophilic condition, the little increase of hydrogen consumption significantly promotes the methane yield from Mb to Md stages (Table 2), but it had weaker impact on microbial composition. This may indicate that the added hydrogen was mainly utilized for methane production other than microbial cell growth. The original mesophilic microbial system was difficult to resist the continuous mixing at Md stage. This speculation need validate in future research.

Dynamic changes of communal microorganisms between mesophilic and thermophilic reactors

Abundance of microorganisms at a phylum and b genus levels in the reactors operating at different fermentative conditions. Microbial groups accounting for less than 1% of all classified sequences are summarized in the group “others.”

Abundance of microorganisms at a phylum and b genus levels in the reactors operating at different fermentative conditions. Microbial groups accounting for less than 1% of all classified sequences are summarized in the group “others.”

Relative abundance and dynamics of microbial taxonomic groups in mesophilic and thermophilic reactors at different operating stages. a Taxonomic classification of microbes reads at domain level. b Taxonomic classification of Euryarchaeota reads at genus level genus level. Bacterial groups accounting for less than 1% of all classified sequences are summarized in the group “others.”

Relative abundance and dynamics of microbial taxonomic groups in mesophilic and thermophilic reactors at different operating stages. a Taxonomic classification of microbes reads at domain level. b Taxonomic classification of Euryarchaeota reads at genus level genus level. Bacterial groups accounting for less than 1% of all classified sequences are summarized in the group “others.”

The same bacteria in both thermophilic and mesophilic reactors including Clostridium_sensu_stricto_1, Marinilabiaceae, Terrisporobacter, and Treponema_2 showed great difference in relative abundance. Clostridium_sensu_stricto_1 and Terrisporobacter, which were the most abundant bacteria in the Ma stage, appeared to decline by half in the Ta stage. Moreover, after H2 addition, the changes in the trends of these two bacteria were completely different: the mesophilic ones increased by approximately 50% until continuous mixing was adopted, whereas the thermophilic ones decreased and Terrisporobacter even fell below 1.8% in the Td stage. Methanosaeta was completely replaced by Methanosarcina, Methanoculleus, Methanobrevibacter, Methanobacterium, and Methanosphaera in the thermophilic reactor. Although Methanosarcina was predominant among methanogens in the Ta stage, the strict hydrogenotrophic methanogens gradually increased to the dominant position after H2 addition (Fig. 4b). This indicates that the added H2 was more favored for hydrogenotrophic methanogenesis in the thermophilic condition, compared to that in mesophilic reactor. Therefore, temperature plays a key role in determining whether the added H2 is utilized directly or not.

In stages without H2 addition, the relative abundance of norank_f_Marinilabiaceae, which mainly involves hydrolysis and proteolytic process [ 35], was 4.89% (Ma) and 10.88% (Ta), respectively, and that of Treponema_2 was 7.10% (Ma) and 4.10% (Ta). However, these two bacteria significantly decreased after H2 addition in the thermophilic stages. In the Td stage, the total relative abundance of these two bacteria was less than 0.06% in the microbial community, which is in stark contrast to the relative abundance of 26% in the Md stage. Methane production increased in the Td stage, but decreased in the Md stage, and this may be because the combination of homoacetogens (HA) and aceticlastic methanogens (AM) was less stable compared with solo hydrogenotrophic methanogens (HM) when continuous mixing was adopted in CSTRs.

Significant differences in microbes between mesophilic and thermophilic reactors

Welch’s t test bar plot on genus level, the microbe’s proportions changed significantly (*p < 0.05, **p < 0.01, ***p < 0.001), was corrected by false discovery rate. a Ma compared to Ta. b Mb compared to Tb. c Mc compared to Tc. d Md compared to Td

Welch’s t test bar plot on genus level, the microbe’s proportions changed significantly (*p < 0.05, **p < 0.01, ***p < 0.001), was corrected by false discovery rate. a Ma compared to Ta. b Mb compared to Tb. c Mc compared to Tc. d Md compared to Td

A previous study reported that Methanosaeta was less competent than Methanosarcina at acetate concentration of over 1 mmol/L [ 11]. In this study, Methanosaeta still dominated in the Ma stage at acetate concentration of over 16 mmol, which indicates that it could surpass Methanosarcina in the CSTR [ 29]. Norank_f_Syntrophomonadaceae plays an important role as syntrophic butyrate-oxidizing bacteria incorporated with Methanosaeta [ 19], and was more abundant in the mesophilic reactor (Fig. 5a). Both Syntrophomonas and norank_f_Syntrophomonadaceae belong to the same family Syntrophomonadaceae however, the former is more favored in thermophilic reactor (Fig. 5c, d) and classified as syntrophic propionic-oxidizing bacteria [ 33].

Psychrobacter, which can efficiently degrade C4–C8 fatty acids in AD process [ 16], was the most abundant species (15.7%) in the Tc stage however, it was not found in the mesophilic reactor. It is interesting to note that Hydrogenispora, which was mainly studied as an H2-promoting bacterium, increased significantly after H2 addition in the thermophilic reactor [ 34]. It increased distinctly (over 20-fold) after H2 added compared with the Ta stage, which is consistent with a previous study which showed that excess Hydrogenispora was probably more favored for H2 consumption rather than H2 production.

The differences in microbial community structure between Mc and Tc

Comparison of the differences in microbial structure between stages Mc and Tc


Culturing Temperature of Yogurt Starters

Thermophilic Cultures = Heat Loving

Thermophilic means heat-loving. This type of culture is added to heated milk and cultured from 5 to 12 hours. Thermophilic cultures typically produce yogurt that is thicker than yogurt from a mesophilic culture. Thermophilic cultures require a consistent heat source to culture properly. A yogurt maker is most typically used for this, but there are ways to culture without a yogurt maker (one way is to use a crockpot!)

Mesophilic Cultures = Medium Loving

Mesophilic means medium-loving, indicating that a mesophilic culture will propagate best at room temperature (around 70° to 77°F).With a mesophilic culture, there is no need to preheat the milk. The culture is simply added to cold milk and cultured at room temperature, usually between 12 and 18 hours. Mesophilic cultures typically produce yogurt that is thinner than yogurt from a thermophilic culture.


How Are Cheese Cultures Classified?

While most cheese cultures have a very similar makeup, they can be differentiated by the temperature at which they work, the type of bacteria strains they contain, and the ratio of each strain present. Depending on the type of cheese you want to make, the type of bacteria strain and ratio of each strain will vary.

Temperature

Cheese cultures can be classified by the temperature at which they work. The two most common type of cheese cultures are:

Mesophilic Culture:

This type of cheese culture is best suited to work in moderate or medium temperatures up to 90°F. It is ideal for making a variety of hard cheeses such as Monterey, Cheddar, Jack, Edam, Gouda, etc. Mesophilic is also the most common of the two cultures as it is used to produce the majority of cheeses that cannot be heated up to a high degree.

Thermophilic Culture:

This type of cheese culture works well with warmer temperatures between 68-125° F range as it is a heat-loving bacteria. It’s used to make a variety of cheeses like Mozzarella, Parmesan, Provolone, Swiss, Romano, and more that can withstand higher temperatures.

For each individual culture, the growth and flavor production range will vary depending on not only the temperature but how many strains of bacteria is used and the ratio of each strain used.

Starter Culture vs. Non Starter Culture

Although it is possible to make cheese without a cheese culture like certain types of fresh, unaged cheeses (cream cheese, cottage cheese, rennet, etc.), most require a starter culture of some sort. Starter culture is specially grown bacteria (LAB or lactic acid bacteria) that is used to start the transformation of milk into cheese. These are great for beginners or if you’re just simply looking for a straightforward way to get started on making your own cheese! Most starter cultures come with a specific blend of bacteria that can be used to make a particular type of cheese. However, some starter cultures have a more broad use such as Mesophilic culture that can be used for a variety of cheese recipes ranging from semi-soft to hard. Many cheese recipes also typically list out the type of cheese culture that is needed in order to create your own, taking the guesswork out of your hands!

By contrast, non-starter culture (NSLAB or non-starter lactic acid bacteria) is made out of the microbial groups that are lower in curds and have different conditions than that of their counterparts. According to the National Center for Biotechnology Information, this type of culture dominates the cheese microbiota during the ripening process by being able to tolerate a hostile environment which strongly influences curd maturations and contributes to the development of the cheese’s final characteristics 1 .


TYPES OF Kefir & Yogurt STARTER CULTURES

Milk Kefir

Milk Kefir is a mesophilicculture, which means it cultures at room temperature, despite which type of starter culture you use.

Yogurt

There are two types of yogurt starters: mesophilic and thermophilic. Mesophilic means that the yogurt starter is cultured at room temperature. Thermophilic means the yogurt starter is heat-loving. This type of yogurt starter is best prepared in a yogurt maker or similar appliance and it will culture at around 110ºF.


Industrial Applications of Thermostable Enzymes from Extremophilic Microorganisms

Author(s): Nasser E. Ibrahim, Department of Biology, University of Waterloo, Waterloo, ON N2L 3G1,, Canada Kesen Ma* Department of Biology, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada

Affiliation:

Journal Name: Current Biochemical Engineering

Volume 4 , Issue 2 , 2017




Graphical Abstract:

Abstract:

Background: Enzymes are biomolecules functioning as catalysts accelerating the speed of specific reactions. Increasing global population, lifestyle trends, biofuels and chemical/pharmaceutical applications have positive impacts on global demand for new industrial enzymes. The global market of enzymes has been growing, which is estimated in 2015 to be about 3.7 billion USD with a 10% expansion.

Objectives: In this review, we discuss the thermophilic and hyperthermophilic enzymes with respect to their sources, applications, and methods for improvement. Prospective enzymes that have potential industrial applications and industries that need new candidate thermophilic enzymes will also be presented.

Results: Research, reports and online contents related to industrial enzymes are reviewed. Industrial enzymes have many applications such as detergent, food, animal feed, cosmetics, biofuel, medication, pharmaceuticals, technical use, and tools for research and development. Commercially available microbial enzymes are about 200 out of almost 4,000 enzymes known. The recent increase in the global environmental awareness requires industry with environmentally friendly conditions and as-low-aspossible energy consumption, which shed light on the benefits of using enzymes. Microorganisms are major sources for industrial enzymes, especially thermophilic and hyperthermophilic microbes. Thermostable enzymes have many desirable characteristics such as thermostability, wide range of pH tolerance and resistance to organic solvents, which make them superior for industrial applications.

Conclusion: Thermophilic and hyperthermophilic enzymes represent a superior source for industrial applications. More efforts are needed for increasing the implementation of thermophilic and hyperthermophilic enzymes in industries, and screening for new enzymes from different sources and creating new methods for harnessing these enzymes for more industrial applications.

Current Biochemical Engineering

Title:Industrial Applications of Thermostable Enzymes from Extremophilic Microorganisms

VOLUME: 4 ISSUE: 2

Author(s):Nasser E. Ibrahim and Kesen Ma*

Affiliation:Department of Biology, University of Waterloo, Waterloo, ON N2L 3G1,, Department of Biology, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1

Abstract:Background: Enzymes are biomolecules functioning as catalysts accelerating the speed of specific reactions. Increasing global population, lifestyle trends, biofuels and chemical/pharmaceutical applications have positive impacts on global demand for new industrial enzymes. The global market of enzymes has been growing, which is estimated in 2015 to be about 3.7 billion USD with a 10% expansion.

Objectives: In this review, we discuss the thermophilic and hyperthermophilic enzymes with respect to their sources, applications, and methods for improvement. Prospective enzymes that have potential industrial applications and industries that need new candidate thermophilic enzymes will also be presented.

Results: Research, reports and online contents related to industrial enzymes are reviewed. Industrial enzymes have many applications such as detergent, food, animal feed, cosmetics, biofuel, medication, pharmaceuticals, technical use, and tools for research and development. Commercially available microbial enzymes are about 200 out of almost 4,000 enzymes known. The recent increase in the global environmental awareness requires industry with environmentally friendly conditions and as-low-aspossible energy consumption, which shed light on the benefits of using enzymes. Microorganisms are major sources for industrial enzymes, especially thermophilic and hyperthermophilic microbes. Thermostable enzymes have many desirable characteristics such as thermostability, wide range of pH tolerance and resistance to organic solvents, which make them superior for industrial applications.

Conclusion: Thermophilic and hyperthermophilic enzymes represent a superior source for industrial applications. More efforts are needed for increasing the implementation of thermophilic and hyperthermophilic enzymes in industries, and screening for new enzymes from different sources and creating new methods for harnessing these enzymes for more industrial applications.


Store Bought Kefir vs Homemade Kefir

For our health-conscious probiotic drinkers, if you’re wondering which is the better option: store bought kefir or homemade kefir, we’re here to give you the rundown! Due to its processing and packaging, store bought kefir has a lower potency, is not carbonated, and has a longer shelf life. Store bought kefir only yields about 10 strains versus homemade genuine kefir typically yields 40-60 strains which is a significant difference! With more strains of bacteria and yeasts, you receive a higher nutritional value than commercial kefir provides. You’ll also notice that most commercial kefir is not carbonated as this is because store bought kefir is limited by the bottling and manufacturing process. Although this may not be a discerning factor for you, if you decide to make your own kefir at home you have the option to make it carbonated.

Homemade kefir is also the healthier and safer option if you have dietary restrictions such as lactose intolerance, or if you’re diabetic and need to be diligent about your sugar consumption.

Most milk kefirs can also be substituted with non-dairy milk such as coconut, almond, soy, and these alternatives have proven to culture successfully. As with most DIY projects, you have complete control over the exact ingredients that you will be using in your kefir--a major advantage that comes with making your own kefir. Another benefit of homemade kefir is that you get to add fruits to make your beverage more flavorful and custom to your liking. While most local supermarkets and grocery stores carry different flavors and varieties of kefir, it does not come close in comparison to fruity homemade kefir all without the unnecessary sugar or additives!

Easy To Make At Home Kefir

Unlike other fermented probiotic-rich beverages like kombucha, homemade kefir is simple to make because it only requires two key ingredients and minimal equipment. To make your own kefir from home you will need:

  1. Whole Milk, Cow’s Milk, or Goat Milk- We recommend to use 1%, 2% or whole milk. Lactose-free milk, ultra-pasteurized, and skim milk is not recommended. Coconut or almond milk may be used. The thickness of your kefir will depend on the type of milk you use. To get started, you will only need 2 teaspoons of kefir grains! Always use fresh kefir grains instead of dehydrated ones.
  2. Mason Jar or Wide-Mouth Jar- Preserve the rich taste and quality of your kefir by using BPA-free glass and use a wide mouth so you have more space to work with.
  3. Cloth or Plastic Lids- Use a cloth or plastic lid to cover your kefir and keep it enclosed tight to start the fermentation process.
  4. Plastic Mesh Strainer or Stainless Steel- Only use plastic or stainless steel. Try to avoid fine mesh or metal strainers because they make straining more difficult due to their small size.
  5. Plastic or Wooden Spoon- When handling kefir, never use a metal spoon.

To save time and money, you can purchase a starter kit with all of your kefir supplies to get started right away!

Whether you choose to purchase each item separately or a starter kit, making your own kefir at home doesn’t require many ingredients and you may already have the majority of these supplies at home! For in-depth step-by-step instructions, learn how to start making your own kefir here.

Cost Efficient

One of the most significant factors in deciding whether it is worth it to start producing your own kefir or stick to the commercial kefir is cost. On average, one bottle of kefir is 32 oz. and costs about $3.99, which equates to approximately 12 cents per ounce. Depending on how much kefir you drink will determine which option is most affordable for you. For example, if you drink one bottle of kefir per week, that would cost you $20 per month and $240 per year. While this may not seem like much, if you drink two or three bottles of kefir per week, then you’re looking to spend about $8-12 per week that comes out to $40-60 per month, which averages out to approximately $480-$720 per year. On the other hand, depending on how much kefir you drink, the cost associated with purchasing milk and kefir grains to produce your own kefir comes out to $60-$100 a year for the same amount which is significantly less expensive. Even if you choose to take the self-starter kit route it still comes out to be more affordable than store bought kefir because most starter kefir packets are about $27-30, and when you factor in the cost of milk it would cost about $99-135 for the same amount. Let’s take a look at the breakdown.

Option A: Purchase Each Item Separately

Whole Milk or Cow’s Milk- (Local Grocery Store or Supermarket: $3.27- reg./ $4.08- organic)

Mason Jar- (Walmart or Target- $4.19)

Cloth or Plastic Lids- (Walmart or Target- $2-4)

Plastic or Stainless Steel Strainer- (Walmart or Target- $3-4)

Plastic or Wooden Spoon- (Walmart or Target- $2-5)

Option B: Purchase a Starter Kit

Regardless of which option you choose, you could still be saving yourself hundreds of dollars if you made your own kefir at home! Kefir is one of the easiest gut-friendly probiotic drinks to make available. Once you get the feel for it, the process becomes simple and enjoyable! Then, you can get creative by experimenting with different flavors, fruits, and milk to cater to your dietary and personal preferences.

Health Benefits of Homemade Kefir

Kefir is packed with a variety of health benefits--it’s one of the main reasons why people drink it! Below are only a few of the benefits you can expect when you drink kefir on a daily basis.

  1. Potent In Antibacterial Properties
    Kefir has many probiotics, some of which are believed to protect against infections. Studies have shown that when harmful bacteria presents itself in our bodies, Lactobacillus kefri, an active probiotic in kefir may help prevent its growth. Kefiran, another active ingredient in kefir also has antibacterial properties.
  2. Low In Lactose
    For those who have lactose intolerance or other dietary restrictions, this may surprise you! While dairy products made with milk typically have a lot of lactose in them, kefir is quite the opposite. This is due to the fact that the lactic acid bacteria found in fermented dairy foods (like yogurt and kefir) transform the lactose into lactic acid, making these foods lower in their lactose content than milk. Kefir also contains enzymes which helps significantly in breaking down the lactose. In addition, it is possible to make 100% lactose-free kefir using coconut water or a non-dairy beverage of your choice.
  3. Helps with Digestive Issues & Gut Health
    This one is probably the most well-known of them all. If you’re experiencing digestive issues or need to reset your gut, kefir is very effective in aiding with this. Kefir has been proven to treat many forms of diarrhea including irritable bowel syndrome (IBS). The probiotics in kefir help restore the good bacteria in your gut. Ample evidence has shown that probiotic-rich foods and probiotics in general can alleviate many digestive problems.
  4. More Powerful Probiotic than Yogurt
    While yogurt is one of the best known probiotic foods, kefir is a more potent source. Kefir grains contain up to 61 strains of bacteria and yeasts, which makes them a diverse and rich probiotic source. Probiotics have a positive influence on many areas of your health, not just your gut, such as that it aids in weight management, digestion, mental health, etc. Whereas, other fermented dairy products don’t contain any yeasts and are made from far fewer strains.
  5. A Great Source of Many Nutrients
    Traditional kefir is made using goat’s or cow’s milk, that makes it easier to ferment. This fermented drink is made by adding kefir grains to milk as we’ve covered throughout this article, but what happens when you add them in? Over a 24-hour period, the microorganisms in the kefir grains multiply and ferment the sugars in the milk turning them into kefir. From there, you get a low-fat, probiotic beverage that is nutrient-dense with calcium, protein, vitamin B12, magnesium, and several others! Although kefir may taste like a liquid form of a yogurt it has a more sour taste and thinner consistency

Why Should You Make Kefir at Home?

If you were wondering why you should make kefir at home, we hope the health benefits, cost factors, and practicality process has convinced you! Bottom line-- kefir is easy to make at home, it’s packed with nutrients, and has many health benefits. Even if you cannot consume animal products or need dairy-free options, we have alternatives for you! Our dry-kefir culture or other vegan options may be a better fit for your lifestyle. Whether you’re a novice learning how to make your own kefir or a professional, we’ve got the right tools, kits, supplies, and recipes for you!


Watch the video: Προβιοτικά στη διατροφή πηγές u0026 οφέλη (August 2022).