Project description:This study describes a transcriptome-phenotype matching approach in which the starter L. lactis MG1363 was fermented under a variety of conditions that differed in the levels of oxygen and/or salt, as well as the fermentation pH and temperature. Samples derived from these fermentations in the exponential phase of bacterial growth were analyzed by full-genome transcriptomics and the assessment of heat and oxidative stress phenotypes. Variations in the fermentation conditions resulted in up to 1000-fold differences in survival during heat and oxidative stress. More specifically, aeration during fermentation induced protection against heat stress, whereas a relatively high fermentation temperature resulted in enhanced robustness towards oxidative stress. Concomitantly, oxygen levels and fermentation temperature induced differential expression of markedly more genes when compared with the other fermentation parameters. Correlation analysis of robustness phenotypes and gene expression levels revealed transcriptome signatures for oxidative and/or heat stress survival, including the metC-cysK operon involved in methionine and cysteine metabolism. To validate this transcriptome-phenotype association we grew L. lactis MG1363 in the absence of cysteine which led to enhanced robustness towards oxidative stress. Conclusions Overall, we demonstrated the importance of careful selection of fermentation parameters prior to industrial processing of starter cultures. Furthermore, established stress genes as well as novel genes were associated with robustness towards heat and/or oxidative stress. Assessment of the expression levels of this group of genes could function as an indicator for enhanced selection of fermentation parameters resulting in improved robustness during spray drying. The increased robustness after growth without cysteine appeared to confirm the role of expression of the metC-cysK operon as an indicator of robustness and suggests that sulfur amino acid metabolism plays a pivotal role in oxidative stress survival.
Project description:This study describes a transcriptome-phenotype matching approach in which the starter L. lactis MG1363 was fermented under a variety of conditions that differed in the levels of oxygen and/or salt, as well as the fermentation pH and temperature. Samples derived from these fermentations in the exponential phase of bacterial growth were analyzed by full-genome transcriptomics and the assessment of heat and oxidative stress phenotypes. Variations in the fermentation conditions resulted in up to 1000-fold differences in survival during heat and oxidative stress. More specifically, aeration during fermentation induced protection against heat stress, whereas a relatively high fermentation temperature resulted in enhanced robustness towards oxidative stress. Concomitantly, oxygen levels and fermentation temperature induced differential expression of markedly more genes when compared with the other fermentation parameters. Correlation analysis of robustness phenotypes and gene expression levels revealed transcriptome signatures for oxidative and/or heat stress survival, including the metC-cysK operon involved in methionine and cysteine metabolism. To validate this transcriptome-phenotype association we grew L. lactis MG1363 in the absence of cysteine which led to enhanced robustness towards oxidative stress. Conclusions Overall, we demonstrated the importance of careful selection of fermentation parameters prior to industrial processing of starter cultures. Furthermore, established stress genes as well as novel genes were associated with robustness towards heat and/or oxidative stress. Assessment of the expression levels of this group of genes could function as an indicator for enhanced selection of fermentation parameters resulting in improved robustness during spray drying. The increased robustness after growth without cysteine appeared to confirm the role of expression of the metC-cysK operon as an indicator of robustness and suggests that sulfur amino acid metabolism plays a pivotal role in oxidative stress survival. two connected loops, both containing samples derived on a single day (sample 1-6, sample 7-13)
Project description:To study the characteristics of proteins in Chinese Chixiang-flavor Baijiu fermentation, a label-free quantitative proteomics approach was established to identify proteins in Jiuqu starter and fermented grains.
2019-06-11 | PXD014221 |
Project description:Studies on Chinese traditional fermentation starter,Jiuyao.
Project description:Growth of L. cremoris NCDO712 was not altered when manganese is omitted from its defined medium. This study was conducted in order to compare protein requirements of Lactococcus cremoris NCDO712 to grow in the presence or absence of manganese in defined medium (1% lactose). The majority of protein adaptation involves upregulation of Mn transporters and to a lesser extent various NADH-dependent proteins. Such adaptation is highly relevant for starter culture in dairy fermentation where manganese is limited and NADH homeostasis determines the formation of volatiles during long-term incubation e.g. cheese ripening.
2022-05-16 | PXD030123 | Pride
Project description:Amplicon sequencing of Chinese liquor fermentation starter culture (16s)
| PRJNA1063940 | ENA
Project description:Amplicon sequencing of Chinese liquor fermentation starter culture (its)
Project description:The consumption of fermented food has been linked to positive health outcomes due to a variety of functional properties. Fermented dairy constitutes a major dietary source and contains lactoseas main carbohydrate and living starter cultures. To investigate whether nutritional and microbial modulation impacted intestinal microbiota composition and activity, we employed fecal microbiota fermentations and a dairy model system consisting of lactose and β-galactosidase positive and negative Streptococcus thermophilus. Based on 16S rRNA gene based microbial community analysis, we observed that lactose addition increased the abundance of Bifidobacteriaceae, and of Veillonellaceae and Enterobacteraceae in selected samples. The supplied lactose was hydrolysed within 24 h of fermentation and led to higher expression of community indigenous β-galactosidases. Targeted protein analysis confirmed that bifidobacteria contributed most β-galactosidases together with other taxa including Escherichia coli and Anaerobutyricum hallii. Lactose addition led to 1.1-1.8 fold higher levels of butyrate compared to controls likely due to (i) lactate-crossfeeding and (ii) direct lactose metabolism by butyrate producing Anaerobutyricum and Faecalibacterium spp. Representatives of both genera used lactose to produce butyrate in single cultures. When supplemented at around 5.5 log cells mL-1, S. thermophilus or its beta-galactosidase negative mutant outnumbered the indigenous Streptococcaceae population at the beginning of fermentation but had no impact on lactose utilisation and final SCFA profiles. This study brings forward new fundamental insight into interactions of major constituents of fermented dairy with the intestinal microbiota. We provide evidence that lactose addition increases fecal microbiota production of butyrate through cross-feeding and direct metabolism without contribution of starter cultures.