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Yang H, Hao L, Jin Y, Huang J, Zhou R, Wu C. Functional roles and engineering strategies to improve the industrial functionalities of lactic acid bacteria during food fermentation. Biotechnol Adv 2024; 74:108397. [PMID: 38909664 DOI: 10.1016/j.biotechadv.2024.108397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 05/20/2024] [Accepted: 06/20/2024] [Indexed: 06/25/2024]
Abstract
In order to improve the flavor profiles, food security, probiotic effects and shorten the fermentation period of traditional fermented foods, lactic acid bacteria (LAB) were often considered as the ideal candidate to participate in the fermentation process. In general, LAB strains possessed the ability to develop flavor compounds via carbohydrate metabolism, protein hydrolysis and amino acid metabolism, lipid hydrolysis and fatty acid metabolism. Based on the functional properties to inhibit spoilage microbes, foodborne pathogens and fungi, those species could improve the safety properties and prolong the shelf life of fermented products. Meanwhile, influence of LAB on texture and functionality of fermented food were also involved in this review. As for the adverse effect carried by environmental challenges during fermentation process, engineering strategies based on exogenous addition, cross protection, and metabolic engineering to improve the robustness and of LAB were also discussed in this review. Besides, this review also summarized the potential strategies including microbial co-culture and metabolic engineering for improvement of fermentation performance in LAB strains. The authors hope this review could contribute to provide an understanding and insight into improving the industrial functionalities of LAB.
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Affiliation(s)
- Huan Yang
- College of Biomass Science and Engineering, Sichuan University, Chengdu 610065, China
| | - Liying Hao
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China
| | - Yao Jin
- College of Biomass Science and Engineering, Sichuan University, Chengdu 610065, China
| | - Jun Huang
- College of Biomass Science and Engineering, Sichuan University, Chengdu 610065, China
| | - Rongqing Zhou
- College of Biomass Science and Engineering, Sichuan University, Chengdu 610065, China
| | - Chongde Wu
- College of Biomass Science and Engineering, Sichuan University, Chengdu 610065, China.
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2
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Huang L, Wu Y, Fan Y, Su Y, Liu Z, Bai J, Zhao X, Li Y, Xie X, Zhang J, Chen M, Wu Q. The growth-promoting effects of protein hydrolysates and their derived peptides on probiotics: structure-activity relationships, mechanisms and future perspectives. Crit Rev Food Sci Nutr 2024:1-20. [PMID: 39154217 DOI: 10.1080/10408398.2024.2387328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/19/2024]
Abstract
Lactic acid bacteria (LAB) are the main probiotics currently available in the markets and are essential for maintaining gut health. To guarantee probiotic function, it is imperative to boost the culture yield of probiotic organisms, ensure the sufficient viable cells in commercial products, or develop effective prebiotics. Recent studies have shown that protein hydrolysates and their derived peptides promote the proliferation of probiotic in vitro and the abundance of gut flora. This article comprehensively reviews different sources of protein hydrolysates and their derived peptides as growth-promoting factors for probiotics including Lactobacillus, Bifidobacterium, and Saccharomyces. We also provide a preliminary analysis of the characteristics of LAB proteolytic systems focusing on the correlation between their elements and growth-promoting activities. The structure-activity relationship and underlying mechanisms of growth-promoting peptides and their research perspectives are thoroughly discussed. Overall, this review provides valuable insights into growth-promoting protein hydrolysates and their derived peptides for proliferating probiotics in vivo or in vitro, which may inspire researchers to explore new options for industrial probiotics proliferation, dairy products fermentation, and novel prebiotics development in the future.
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Affiliation(s)
- Lanyan Huang
- Institute of Microbiology, Guangdong Academy of Sciences, State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Safety and Health, National Health Commission Science and Technology Innovation Platform for Nutrition and Safety of Microbial Food, Guangzhou, China
- Guangzhou Institute of Chemistry, Chinese Academy of Sciences, Guangzhou, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yuwei Wu
- Guangdong Huankai Biotechnology Co., Ltd, Guangzhou, China
| | - Yue Fan
- Institute of Microbiology, Guangdong Academy of Sciences, State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Safety and Health, National Health Commission Science and Technology Innovation Platform for Nutrition and Safety of Microbial Food, Guangzhou, China
| | - Yue Su
- Institute of Microbiology, Guangdong Academy of Sciences, State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Safety and Health, National Health Commission Science and Technology Innovation Platform for Nutrition and Safety of Microbial Food, Guangzhou, China
| | - Zihao Liu
- Institute of Microbiology, Guangdong Academy of Sciences, State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Safety and Health, National Health Commission Science and Technology Innovation Platform for Nutrition and Safety of Microbial Food, Guangzhou, China
| | - Jianling Bai
- Institute of Microbiology, Guangdong Academy of Sciences, State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Safety and Health, National Health Commission Science and Technology Innovation Platform for Nutrition and Safety of Microbial Food, Guangzhou, China
| | - Xinyu Zhao
- Guangdong Huankai Biotechnology Co., Ltd, Guangzhou, China
| | - Ying Li
- Institute of Microbiology, Guangdong Academy of Sciences, State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Safety and Health, National Health Commission Science and Technology Innovation Platform for Nutrition and Safety of Microbial Food, Guangzhou, China
| | - Xinqiang Xie
- Institute of Microbiology, Guangdong Academy of Sciences, State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Safety and Health, National Health Commission Science and Technology Innovation Platform for Nutrition and Safety of Microbial Food, Guangzhou, China
| | - Jumei Zhang
- Institute of Microbiology, Guangdong Academy of Sciences, State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Safety and Health, National Health Commission Science and Technology Innovation Platform for Nutrition and Safety of Microbial Food, Guangzhou, China
| | - Moutong Chen
- Institute of Microbiology, Guangdong Academy of Sciences, State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Safety and Health, National Health Commission Science and Technology Innovation Platform for Nutrition and Safety of Microbial Food, Guangzhou, China
| | - Qingping Wu
- Institute of Microbiology, Guangdong Academy of Sciences, State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Safety and Health, National Health Commission Science and Technology Innovation Platform for Nutrition and Safety of Microbial Food, Guangzhou, China
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Melkonian C, Zorrilla F, Kjærbølling I, Blasche S, Machado D, Junge M, Sørensen KI, Andersen LT, Patil KR, Zeidan AA. Microbial interactions shape cheese flavour formation. Nat Commun 2023; 14:8348. [PMID: 38129392 PMCID: PMC10739706 DOI: 10.1038/s41467-023-41059-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Accepted: 08/15/2023] [Indexed: 12/23/2023] Open
Abstract
Cheese fermentation and flavour formation are the result of complex biochemical reactions driven by the activity of multiple microorganisms. Here, we studied the roles of microbial interactions in flavour formation in a year-long Cheddar cheese making process, using a commercial starter culture containing Streptococcus thermophilus and Lactococcus strains. By using an experimental strategy whereby certain strains were left out from the starter culture, we show that S. thermophilus has a crucial role in boosting Lactococcus growth and shaping flavour compound profile. Controlled milk fermentations with systematic exclusion of single Lactococcus strains, combined with genomics, genome-scale metabolic modelling, and metatranscriptomics, indicated that S. thermophilus proteolytic activity relieves nitrogen limitation for Lactococcus and boosts de novo nucleotide biosynthesis. While S. thermophilus had large contribution to the flavour profile, Lactococcus cremoris also played a role by limiting diacetyl and acetoin formation, which otherwise results in an off-flavour when in excess. This off-flavour control could be attributed to the metabolic re-routing of citrate by L. cremoris from diacetyl and acetoin towards α-ketoglutarate. Further, closely related Lactococcus lactis strains exhibited different interaction patterns with S. thermophilus, highlighting the significance of strain specificity in cheese making. Our results highlight the crucial roles of competitive and cooperative microbial interactions in shaping cheese flavour profile.
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Affiliation(s)
- Chrats Melkonian
- Bioinformatics & Modeling, R&D Digital Innovation, Chr. Hansen A/S, 2970, Hørsholm, Denmark.
- Theoretical Biology and Bioinformatics, Science for Life, Utrecht University, Utrecht, the Netherlands.
- Bioinformatics Group, Wageningen University and Research, Wageningen, the Netherlands.
| | - Francisco Zorrilla
- Medical Research Council Toxicology Unit, University of Cambridge, Cambridge, UK
| | - Inge Kjærbølling
- Bioinformatics & Modeling, R&D Digital Innovation, Chr. Hansen A/S, 2970, Hørsholm, Denmark
| | - Sonja Blasche
- Medical Research Council Toxicology Unit, University of Cambridge, Cambridge, UK
- European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117, Heidelberg, Germany
| | - Daniel Machado
- European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117, Heidelberg, Germany
- Department of Biotechnology and Food Science, Norwegian University of Science and Technology, Trondheim, 7491, Norway
| | - Mette Junge
- Strain Improvement, R&D Food Microbiology, Chr. Hansen A/S, 2970, Hørsholm, Denmark
| | - Kim Ib Sørensen
- Strain Improvement, R&D Food Microbiology, Chr. Hansen A/S, 2970, Hørsholm, Denmark
| | | | - Kiran R Patil
- Medical Research Council Toxicology Unit, University of Cambridge, Cambridge, UK
- European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117, Heidelberg, Germany
| | - Ahmad A Zeidan
- Bioinformatics & Modeling, R&D Digital Innovation, Chr. Hansen A/S, 2970, Hørsholm, Denmark.
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Ao XL, Liao YM, Kang HY, Li HL, He T, Zou LK, Liu SL, Chen SJ, Yang Y, Liu XY. Untargeted Metabolomics and Physicochemical Analysis Revealed the Quality Formation Mechanism in Fermented Milk Inoculated with Lactobacillus brevis and Kluyveromyces marxianus Isolated from Traditional Fermented Milk. Foods 2023; 12:3704. [PMID: 37835356 PMCID: PMC10572762 DOI: 10.3390/foods12193704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 09/24/2023] [Accepted: 09/27/2023] [Indexed: 10/15/2023] Open
Abstract
Traditional fermented milk from the western Sichuan plateau of China has a unique flavor and rich microbial diversity. This study explored the quality formation mechanism in fermented milk inoculated with Lactobacillus brevis NZ4 and Kluyveromyces marxianus SY11 (MFM), the dominant microorganisms isolated from traditional dairy products in western nan. The results indicated that MFM displayed better overall quality than the milk fermented with L. brevis NZ4 (LFM) and K. marxianus SY11 (KFM), respectively. MFM exhibited good sensory quality, more organic acid types, more free amino acids and esters, and moderate acidity and ethanol concentrations. Non-targeted metabolomics showed a total of 885 metabolites annotated in the samples, representing 204 differential metabolites between MFM and LFM and 163 between MFM and KFM. MFM displayed higher levels of N-acetyl-L-glutamic acid, cysteinyl serine, glaucarubin, and other substances. The differential metabolites were mainly enriched in pathways such as glycerophospholipid metabolism, arginine biosynthesis, and beta-alanine metabolism. This study speculated that L. brevis affected K. marxianus growth via its metabolites, while the mixed fermentation of these strains significantly changed the metabolism pathway of flavor-related substances, especially glycerophospholipid metabolism. Furthermore, mixed fermentation modified the flavor and quality of fermented milk by affecting cell growth and metabolic pathways.
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Gu Y, Zhang B, Tian J, Li L, He Y. Physiology, quorum sensing, and proteomics of lactic acid bacteria were affected by Saccharomyces cerevisiae YE4. Food Res Int 2023; 166:112612. [PMID: 36914328 DOI: 10.1016/j.foodres.2023.112612] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 02/11/2023] [Accepted: 02/14/2023] [Indexed: 02/25/2023]
Abstract
The interaction mode between lactic acid bacteria (LAB) and yeast in a fermentation system directly determines the quality of the products, thus understanding their mode of interaction can improve product quality. The present study investigated the effects of Saccharomyces cerevisiae YE4 on LAB from the perspectives of physiology, quorum sensing (QS), and proteomics. The presence of S. cerevisiae YE4 slowed down the growth of Enterococcus faecium 8-3 but had no significant effect on acid production or biofilm formation. S. cerevisiae YE4 significantly reduced the activity of autoinducer-2 at 19 h in E. faecium 8-3 and at 7-13 h in Lactobacillus fermentum 2-1. Expression of the QS-related genes luxS and pfs was also inhibited at 7 h. Moreover, a total of 107 E. faecium 8-3 proteins differed significantly in coculture with S. cerevisiae YE4-these proteins are involved in metabolic pathways including biosynthesis of secondary metabolites; biosynthesis of amino acids; alanine, aspartate, and glutamate metabolism; fatty acid metabolism; and fatty acid biosynthesis. Among them, proteins involved in cell adhesion, cell wall formation, two-component systems, and ABC transporters were detected. Therefore, S. cerevisiae YE4 might affect the physiological metabolism of E. faecium 8-3 by affecting cell adhesion, cell wall formation, and cell-cell interactions.
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Affiliation(s)
- Yue Gu
- College of Food Science and Engineering, Inner Mongolia Agricultural University, 306 Zhaowuda Road, Hohhot, Inner Mongolia 010018, China
| | - Baojun Zhang
- College of Food Science and Engineering, Inner Mongolia Agricultural University, 306 Zhaowuda Road, Hohhot, Inner Mongolia 010018, China
| | - Jianjun Tian
- College of Food Science and Engineering, Inner Mongolia Agricultural University, 306 Zhaowuda Road, Hohhot, Inner Mongolia 010018, China
| | - Lijie Li
- College of Food Science and Engineering, Inner Mongolia Agricultural University, 306 Zhaowuda Road, Hohhot, Inner Mongolia 010018, China.
| | - Yinfeng He
- College of Food Science and Engineering, Inner Mongolia Agricultural University, 306 Zhaowuda Road, Hohhot, Inner Mongolia 010018, China.
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Tao Z, Yuan H, Liu M, Liu Q, Zhang S, Liu H, Jiang Y, Huang D, Wang T. Yeast Extract: Characteristics, Production, Applications and Future Perspectives. J Microbiol Biotechnol 2023; 33:151-166. [PMID: 36474327 PMCID: PMC9998214 DOI: 10.4014/jmb.2207.07057] [Citation(s) in RCA: 25] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 10/11/2022] [Accepted: 10/11/2022] [Indexed: 12/13/2022]
Abstract
Yeast extract is a product prepared mainly from waste brewer's yeast, which is rich in nucleotides, proteins, amino acids, sugars and a variety of trace elements, and has the advantages of low production cost and abundant supply of raw material. Consequently, yeast extracts are widely used in various fields as animal feed additives, food flavoring agents and additives, cosmetic supplements, and microbial fermentation media; however, their full potential has not yet been realized. To improve understanding of current research knowledge, this review summarizes the ingredients, production technology, and applications of yeast extracts, and discusses the relationship between their properties and applications. Developmental trends and future prospects of yeast extract are also previewed, with the aim of providing a theoretical basis for the development and expansion of future applications.
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Affiliation(s)
- Zekun Tao
- State Key Laboratory of Bio-Based Material and Green Papermaking (LBMP), Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, Shandong, P.R. China.,Key Laboratory of Shandong Microbial Engineering, School of Bioengineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, Shandong, P.R. China
| | - Haibo Yuan
- State Key Laboratory of Bio-Based Material and Green Papermaking (LBMP), Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, Shandong, P.R. China.,Key Laboratory of Shandong Microbial Engineering, School of Bioengineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, Shandong, P.R. China
| | - Meng Liu
- State Key Laboratory of Bio-Based Material and Green Papermaking (LBMP), Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, Shandong, P.R. China.,Key Laboratory of Shandong Microbial Engineering, School of Bioengineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, Shandong, P.R. China
| | - Qian Liu
- State Key Laboratory of Bio-Based Material and Green Papermaking (LBMP), Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, Shandong, P.R. China.,Key Laboratory of Shandong Microbial Engineering, School of Bioengineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, Shandong, P.R. China
| | - Siyi Zhang
- State Key Laboratory of Bio-Based Material and Green Papermaking (LBMP), Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, Shandong, P.R. China.,Key Laboratory of Shandong Microbial Engineering, School of Bioengineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, Shandong, P.R. China
| | - Hongling Liu
- State Key Laboratory of Bio-Based Material and Green Papermaking (LBMP), Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, Shandong, P.R. China.,Key Laboratory of Shandong Microbial Engineering, School of Bioengineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, Shandong, P.R. China
| | - Yi Jiang
- State Key Laboratory of Bio-Based Material and Green Papermaking (LBMP), Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, Shandong, P.R. China.,Key Laboratory of Shandong Microbial Engineering, School of Bioengineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, Shandong, P.R. China
| | - Di Huang
- State Key Laboratory of Bio-Based Material and Green Papermaking (LBMP), Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, Shandong, P.R. China.,Key Laboratory of Shandong Microbial Engineering, School of Bioengineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, Shandong, P.R. China
| | - Tengfei Wang
- State Key Laboratory of Bio-Based Material and Green Papermaking (LBMP), Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, Shandong, P.R. China.,Key Laboratory of Shandong Microbial Engineering, School of Bioengineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, Shandong, P.R. China
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Gasser C, Garault P, Chervaux C, Monnet V, Faurie JM, Rul F. Co-utilization of saccharides in mixtures: Moving toward a new understanding of carbon metabolism in Streptococcus thermophilus. Food Microbiol 2022; 107:104080. [DOI: 10.1016/j.fm.2022.104080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 05/23/2022] [Accepted: 06/08/2022] [Indexed: 12/01/2022]
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Genome-Scale Metabolic Modeling Combined with Transcriptome Profiling Provides Mechanistic Understanding of Streptococcus thermophilus CH8 Metabolism. Appl Environ Microbiol 2022; 88:e0078022. [PMID: 35924931 PMCID: PMC9477255 DOI: 10.1128/aem.00780-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Streptococcus thermophilus is a lactic acid bacterium adapted toward growth in milk and is a vital component of starter cultures for milk fermentation. Here, we combine genome-scale metabolic modeling and transcriptome profiling to obtain novel metabolic insights into this bacterium. Notably, a refined genome-scale metabolic model (GEM) accurately representing S. thermophilus CH8 metabolism was developed. Modeling the utilization of casein as a nitrogen source revealed an imbalance in amino acid supply and demand, resulting in growth limitation due to the scarcity of specific amino acids, in particular sulfur amino acids. Growth experiments in milk corroborated this finding. A subtle interdependency of the redox balance and the secretion levels of the key metabolites lactate, formate, acetoin, and acetaldehyde was furthermore identified with the modeling approach, providing a mechanistic understanding of the factors governing the secretion product profile. As a potential effect of high expression of arginine biosynthesis genes, a moderate secretion of ornithine was observed experimentally, augmenting the proposed hypothesis of ornithine/putrescine exchange as part of the protocooperative interaction between S. thermophilus and Lactobacillus delbrueckii subsp. bulgaricus in yogurt. This study provides a foundation for future community modeling of food fermentations and rational development of starter strains with improved functionality. IMPORTANCEStreptococcus thermophilus is one the main organisms involved in the fermentation of milk and, increasingly, also in the fermentation of plant-based foods. The construction of a functional high-quality genome-scale metabolic model, in conjunction with in-depth transcriptome profiling with a focus on metabolism, provides a valuable resource for the improved understanding of S. thermophilus physiology. An example is the model-based prediction of the most significant route of synthesis for the characteristic yogurt flavor compound acetaldehyde and identification of metabolic principles governing the synthesis of other flavor compounds. Moreover, the systematic assessment of amino acid supply and demand during growth in milk provides insights into the key challenges related to nitrogen metabolism that is imposed on S. thermophilus and any other organism associated with the milk niche.
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Three Distinct Proteases Are Responsible for Overall Cell Surface Proteolysis in Streptococcus thermophilus. Appl Environ Microbiol 2021; 87:e0129221. [PMID: 34550764 DOI: 10.1128/aem.01292-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The lactic acid bacterium Streptococcus thermophilus was believed to display only two distinct proteases at the cell surface, namely, the cell envelope protease PrtS and the housekeeping protease HtrA. Using peptidomics, we demonstrate here the existence of an additional active cell surface protease, which shares significant homology with the SepM protease of Streptococcus mutans. Although all three proteases-PrtS, HtrA, and SepM-are involved in the turnover of surface proteins, they demonstrate distinct substrate specificities. In particular, SepM cleaves proteins involved in cell wall metabolism and cell elongation, and its inactivation has consequences for cell morphology. When all three proteases are inactivated, the residual cell-surface proteolysis of S. thermophilus is approximately 5% of that of the wild-type strain. IMPORTANCE Streptococcus thermophilus is a lactic acid bacterium used widely as a starter in the dairy industry. Due to its "generally recognized as safe" status and its weak cell surface proteolytic activity, it is also considered a potential bacterial vector for heterologous protein production. Our identification of a new cell surface protease made it possible to construct a mutant strain with a 95% reduction in surface proteolysis, which could be useful in numerous biotechnological applications.
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Carpinelli NA, Halfen J, Trevisi E, Chapman JD, Sharman ED, Anderson JL, Osorio JS. Effects of peripartal yeast culture supplementation on lactation performance, blood biomarkers, rumen fermentation, and rumen bacteria species in dairy cows. J Dairy Sci 2021; 104:10727-10743. [PMID: 34253357 DOI: 10.3168/jds.2020-20002] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 05/24/2021] [Indexed: 12/16/2022]
Abstract
Feeding yeast culture fermentation products has been associated with improved feed intake and milk yield in transition dairy cows. These improvements in performance have been further described in terms of rumen characteristics, metabolic profile, and immune response. The objective of this study was to evaluate the effects of a commercial yeast culture product (YC; Culture Classic HD, Phibro Animal Health) on performance, blood biomarkers, rumen fermentation, and rumen bacterial population in dairy cows from -30 to 50 d in milk (DIM). Forty Holstein dairy cows were enrolled in a randomized complete block design from -30 to 50 DIM and blocked according to expected calving day, parity, previous milk yield, and genetic merit. At -30 DIM, cows were assigned to either a basal diet plus 114 g/d of ground corn (control; n = 20) or a basal diet plus 100 g/d of ground corn and 14 g/d of YC (n = 20), fed as a top-dress. Cows received the same close-up diet from 30 d prepartum until calving [1.39 Mcal/kg of dry matter (DM) and 12.3% crude protein (CP)] and lactation diet from calving to 50 DIM (1.60 Mcal/kg of DM and 15.6% CP). Blood samples and rumen fluid were collected at various time points from -30 to 50 d relative to calving. Cows fed YC compared with control showed a trend for increased energy-corrected milk (+3.2 kg/d). Lower somatic cell counts were observed in YC cows than in control. We detected a treatment × time interaction in nonesterified fatty acids (NEFA) that could be attributed to a trend for greater NEFA in YC cows than control at 7 DIM, followed by lower NEFA in YC cows than control at 14 and 30 DIM. In the rumen, YC contributed to mild changes in rumen fermentation, mainly increasing postpartal valerate while decreasing prepartal isovalerate. This was accompanied by alterations in rumen microbiota, including a greater abundance of cellulolytic (Fibrobacter succinogenes) and lactate-utilizing bacteria (Megasphaera elsdenii). These results describe the potential benefits of supplementing yeast culture during the late pregnancy through early lactation, at least in terms of rumen environment and performance.
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Affiliation(s)
- N A Carpinelli
- Department of Dairy and Food Sciences, South Dakota State University, Brookings 57007
| | - J Halfen
- Department of Dairy and Food Sciences, South Dakota State University, Brookings 57007; Núcleo de Pesquisa, Ensino e Extenssão em Pecuária, Universidade Federal de Pelotas, Pelotas, Rio Grande do Sul, Brazil 96010610
| | - E Trevisi
- Department of Animal Sciences, Food and Nutrition (DIANA), Facoltà di Scienze Agrarie, Alimentari e Ambientali, Università Cattolica del Sacro Cuore, 29122 Piacenza, Italy
| | | | | | - J L Anderson
- Department of Dairy and Food Sciences, South Dakota State University, Brookings 57007
| | - J S Osorio
- Department of Dairy and Food Sciences, South Dakota State University, Brookings 57007.
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