Genome Sequence of Lactobacillus sakei subsp. sakei LS25, a Commercial Starter Culture Strain for Fermented Sausage

Integrated Phenotypic-Genotypic Analysis of Latilactobacillus sakei from Different Niches

Increasing attention has been paid to the potential probiotic effects of Latilactobacillus sakei. To explore the genetic diversity of L. sakei, 14 strains isolated from different niches (feces, fermented kimchi, and meat products) and 54 published strains were compared and analyzed. The results showed that the average genome size and GC content of L. sakei were 1.98 Mb and 41.22%, respectively. Its core genome mainly encodes translation and transcription, amino acid synthesis, glucose metabolism, and defense functions. L. sakei has open pan-genomic characteristics, and its pan-gene curve shows an upward trend. The genetic diversity of L. sakei is mainly reflected in carbohydrate utilization, antibiotic tolerance, and immune/competition-related factors, such as clustering regular interval short palindromic repeat sequence (CRISPR)-Cas. The CRISPR system is mainly IIA type, and a few are IIC types. This work provides a basis for the study of this species.

Genome Sequencing of Kocuria varians Strain 80, Isolated from Starter Culture for Dry Sausage

The genome of the meat starter culture strain Kocuria varians 80 was sequenced and assembled into a single 2.82-Mb chromosome. Genome sequence comparison of K. varians strain 80 and previously sequenced strains revealed predicted proteomic differences that can impact its technological properties.

The genome of the meat starter culture strain Kocuria varians 80 was sequenced and assembled into a single 2.82-Mb chromosome. Genome sequence comparison of K. varians strain 80 and previously sequenced strains revealed predicted proteomic differences that can impact its technological properties.

Use of recombinant Lactobacillus sakei for the prevention and treatment of radiation-induced enteritis

Radiation-induced enteritis is one of the most common complications in patients under radiotherapy at abdominal or pelvic cavity. Up to 50% of patients treated with pelvic radiotherapy has been reported radiation-induced acute enteritis, and half of them developed chronic enteritis. Overproduction of free radicals, activation of inflammatory pathways and vascular endothelial dysfunction were considered as the primary mechanisms of radiation-induced enteritis. Because probiotics have been demonstrated as a promising potential candidate for treating intestinal diseases, it may be a safer and more effective radioprotector for the enteritis compared to conventional chemical agents with inherent toxicities. Here, we propose that a recombinant Lactobacillus sakei would decrease the complications or symptoms significantly through against different pathogenic mechanisms simultaneously. Therefore, application of higher radiation dose for tumor control would be feasible when co-treating with recombinant Lactobacillus sakei.

Effects of glucose availability in Lactobacillus sakei; metabolic change and regulation of the proteome and transcriptome

Effects of glucose availability were investigated in Lactobacillus sakei strains 23K and LS25 cultivated in anaerobic, glucose-limited chemostats set at high (D = 0.357 h-1) and low (D = 0.045 h-1) dilution rates. We observed for both strains a shift from homolactic towards more mixed acid fermentation when comparing high to low growth rates. However, this change was more pronounced for LS25 than for 23K, where dominating products were lactate>formate>acetate≥ethanol at both conditions. A multivariate approach was used for analyzing proteome and transcriptome data from the bacterial cultures, where the predictive power of the omics data was used for identifying features that can explain the differences in the end-product profiles. We show that the different degree of response to the same energy restriction revealed interesting strain specific regulation. An elevated formate production level during slow growth, more for LS25 than for 23K, was clearly reflected in correlating pyruvate formate lyase expression. With stronger effect for LS25, differential expression of the Rex transcriptional regulator and NADH oxidase, a target of Rex, indicated that maintainance of the cell redox balance, in terms of the NADH/NAD+ ratio, may be a key process during the metabolic change. The results provide a better understanding of different strategies that cells may deploy in response to changes in substrate availability.

Lactobacillus sakei: A Starter for Sausage Fermentation, a Protective Culture for Meat Products

Among lactic acid bacteria of meat products, Lactobacillus sakei is certainly the most studied species due to its role in the fermentation of sausage and its prevalence during cold storage of raw meat products. Consequently, the physiology of this bacterium regarding functions involved in growth, survival, and metabolism during meat storage and processing are well known. This species exhibits a wide genomic diversity that can be observed when studying different strains and on which probably rely its multiple facets in meat products: starter, spoiler, or protective culture. The emerging exploration of the microbial ecology of meat products also revealed the multiplicity of bacterial interactions L. sakei has to face and their various consequences on microbial quality and safety at the end of storage.

The Use of Starter Cultures in Traditional Meat Products

Starter cultures could play an essential role in the manufacture of traditional cured meat products. In order to achieve objectives related to meat products’ quality and safety improvement, the selection of particular strains constituting a starter culture should be carried out in the context of its application, since its functionality will depend on the type of sausage and process conditions. Also, strain selection should comply with particular requirements to warrant safety. The aim of the current review is to update the knowledge on the use of starter cultures in traditional meat products, with focus on dry-fermented products. In this manuscript, we will try to give answers to some relevant questions: Which starter cultures are used and why? Why are LAB used? What are their role and their specific mode of action? Which other groups of microorganisms (bacteria and fungi) are used as starter cultures and how do they act? A particular revision of omics approach regarding starter cultures is made since the use of these techniques allows rapid screening of promising wild strains with desirable functional characteristics, enabling the development of starter cultures better adapted to the meat matrix.