Ligilactobacillus cholophilus sp. nov., isolated from pickled potherb mustard (Brassica juncea Coss.)

Strain BD7642T was isolated from Chinese pickled potherb mustard (Brassica juncea Coss.) purchased from a local market in Shanghai, PR China. A polyphasic approach, including 16S rRNA gene sequence, housekeeping gene, average nucleotide identity (ANI), digital DNA-DNA hybridization (dDDH), G+C content and phenotypic analyses, was employed to characterize strain BD7642T. Cells of the bacterium were short round rods, Gram-stain-positive, non-spore-forming and catalase-negative. The strain grew at 30-45 °C and pH 4.0-8.0. Optimum growth occurred at 35-40 °C and pH 6.0-7.0. The strain exhibited growth with salt (NaCl) concentrations of up to 5 % (w/v). The G+C content of the strain's genomic DNA was 31.37 mol%. The major fatty acids were C16 : 0, C18 : 1 c9 and summed feature 10 (C18 : 1 c11/t9/t6). 16S rRNA gene sequencing revealed that strain BD7642T represents a member of the genus Ligilactobacillus and it had high sequence similarity to Ligilactobacillus aviarius NBRC 102162T (96.73 %), Ligilactobacillus araffinosus LGM 23560 (96.66 %) and Ligilactobacillus salivarius JCM 1231T (95.82 %). The dDDH values between strain BD7642T and its phylogenetically related species within the genus Ligilactobacillus ranged from 12.6 to 25.4 %. The ANI values between strain BD7642T and its closely related taxa were far lower than the threshold (95 %-96 %) used for species differentiation. Results of phylogenetic, physiological and phenotypic characterization confirmed that strain BD7642T represents a novel species within the genus Ligilactobacillus, for which the name Ligilactobacillus cholophilus sp. nov. is proposed. The type strain is BD7642T (=CCTCC AB 2022398T=JCM 36074T).

A novel species of lactic acid bacteria, Ligilactobacillus pabuli sp. nov., isolated from alfalfa silage

In this study, we isolated a novel strain of lactic acid bacteria, AF129T, from alfalfa silage prepared locally in Morioka, Iwate, Japan. Polyphasic taxonomy was used to characterize the bacterial strain. The bacterium was rod-shaped, Gram-stain-positive, non-spore-forming and catalase-negative. The strain grew at various temperatures (15–40°C) and pH levels (4.0–8.0). The optimum growth conditions were a temperature of 30°C and a pH of 6.0. AF129T exhibited growth at salt (NaCl) concentrations of up to 6.5 % (w/v). The G+C content of the strain’s genomic DNA was 41.5 %. The major fatty acids were C16 : 0, C18 : 1ω9c, C19 : 0cyclo ω8c and summed feature 8. 16S rRNA gene sequencing revealed that AF129T represents a member of the genus Ligilactobacillus and it has higher sequence similarities with Ligilactobacillus pobuzihii (98.4 %), Ligilactobacillus acidipiscis (97.5 %) and Ligilactobacillus salitolerans (97.4 %). The digital DNA–DNA hybridization values for AF129T and phylogenetically related species of the genus Ligilactobacillus ranged from 19.8% to 24.1%. The average nucleotide identity of the strain with its closely related taxa was lower than the threshold (95 %–96 %) used for species differentiation. In the light of the above-mentioned physiological, genotypic, chemotaxonomic and phylogenetic evidence, we confirm that AF129T represents a member of the genus Ligilactobacillus and constitutes a novel species; we propose the name Ligilactobacillus pabuli sp. nov. for this species. The type strain is AF129T =MAFF 518002T =JCM 34518T=BCRC 81335T.

Comparative Genomic Analysis Reveals Intestinal Habitat Adaptation of Ligilactobacillus equi Rich in Prophage and Degrading Cellulase

Ligilactobacillus equi is common in the horse intestine, alleviates the infection of Salmonella, and regulates intestinal flora. Despite this, there have been no genomic studies on this species. Here, we provide the genomic basis for adaptation to the intestinal habitat of this species. We sequenced the genome of L. equi IMAU81196, compared this with published genome information from three strains in NCBI, and analyzed genome characteristics, phylogenetic relationships, and functional genes. The mean genome size of L. equi strains was 2.08 ± 0.09 Mbp, and the mean GC content was 39.17% ± 0.19%. The genome size of L. equi IMAU81196 was 1.95 Mbp, and the GC content was 39.48%. The phylogenetic tree for L. equi based on 1454 core genes showed that the independent branch of strain IMAU81196 was far from the other three strains. In terms of genomic characteristics, single-nucleotide polymorphism (SNP) sites, rapid annotation using subsystem technology (RAST), carbohydrate activity enzymes (CAZy), and predictions of prophage, we showed that strain L. equi JCM 10991T and strain DSM 15833T are not equivalent strains.It is worth mentioning thatthestrain of L. equi has numerous enzymes related to cellulose degradation, and each L. equi strain investigated contained at least one protophage. We speculate that this is the reason why these strains are adapted to the intestinal environment of horses. These results provide new research directions for the future.

A taxonomic note on the genus Lactobacillus: Description of 23 novel genera, emended description of the genus Lactobacillus Beijerinck 1901, and union of Lactobacillaceae and Leuconostocaceae

The genus Lactobacillus comprises 261 species (at March 2020) that are extremely diverse at phenotypic, ecological and genotypic levels. This study evaluated the taxonomy of Lactobacillaceae and Leuconostocaceae on the basis of whole genome sequences. Parameters that were evaluated included core genome phylogeny, (conserved) pairwise average amino acid identity, clade-specific signature genes, physiological criteria and the ecology of the organisms. Based on this polyphasic approach, we propose reclassification of the genus Lactobacillus into 25 genera including the emended genus Lactobacillus, which includes host-adapted organisms that have been referred to as the Lactobacillus delbrueckii group, Paralactobacillus and 23 novel genera for which the names Holzapfelia, Amylolactobacillus, Bombilactobacillus, Companilactobacillus, Lapidilactobacillus, Agrilactobacillus, Schleiferilactobacillus, Loigolactobacilus, Lacticaseibacillus, Latilactobacillus, Dellaglioa, Liquorilactobacillus, Ligilactobacillus, Lactiplantibacillus, Furfurilactobacillus, Paucilactobacillus, Limosilactobacillus, Fructilactobacillus, Acetilactobacillus, Apilactobacillus, Levilactobacillus, Secundilactobacillus and Lentilactobacillus are proposed. We also propose to emend the description of the family Lactobacillaceae to include all genera that were previously included in families Lactobacillaceae and Leuconostocaceae. The generic term 'lactobacilli' will remain useful to designate all organisms that were classified as Lactobacillaceae until 2020. This reclassification reflects the phylogenetic position of the micro-organisms, and groups lactobacilli into robust clades with shared ecological and metabolic properties, as exemplified for the emended genus Lactobacillus encompassing species adapted to vertebrates (such as Lactobacillus delbrueckii, Lactobacillus iners, Lactobacillus crispatus, Lactobacillus jensensii, Lactobacillus johnsonii and Lactobacillus acidophilus) or invertebrates (such as Lactobacillus apis and Lactobacillus bombicola).

Lactobacillus salitolerans sp. nov., a novel lactic acid bacterium isolated from spent mushroom substrates

A taxonomic study of a Gram-stain-positive, rod-shaped, non-motile, non-spore-forming, catalase-negative bacterium, strain YK43T, isolated from spent mushroom substrates stored in Nagano, Japan was performed. Growth was detected at 15–45 °C, pH 5.0–8.5, and 0–10 % (w/v) NaCl. The genomic DNA G+C content of strain YK43T was 43.6 mol%. The predominant fatty acids were C16 : 0, C18 : 1 ω9c and summed feature 8. Based on 16S rRNA gene sequence analysis, the type strains of Lactobacillus acidipiscis (sequence similarity, 97.6 %) and Lactobacillus pobuzihii (97.4 %) were most closely related to YK43T. The average nucleotide identities were 74.1 % between strain YK43T and L. acidipiscis DSM 15836T and 74.0 % between YK43T and L. pobuzihii E100301T. Based on a multilocus sequence analysis, comparative genomic analysis and a range of phenotypic and chemotaxonomic characteristics, strain YK43T represents a novel species of the genus Lactobacillus , for which the name Lactobacillus salitolerans sp. nov. is proposed. The type strain is YK43T (=JCM 31331T = DSM 103433T).

Mining metagenomic whole genome sequences revealed subdominant but constant Lactobacillus population in the human gut microbiota

The genus Lactobacillus includes over 215 species that colonize plants, foods, sewage and the gastrointestinal tract (GIT) of humans and animals. In the GIT, Lactobacillus population can be made by true inhabitants or by bacteria occasionally ingested with fermented or spoiled foods, or with probiotics. This study longitudinally surveyed Lactobacillus species and strains in the feces of a healthy subject through whole genome sequencing (WGS) data-mining, in order to identify members of the permanent or transient populations. In three time-points (0, 670 and 700 d), 58 different species were identified, 16 of them being retrieved for the first time in human feces. L. rhamnosus, L. ruminis, L. delbrueckii, L. plantarum, L. casei and L. acidophilus were the most represented, with estimated amounts ranging between 6 and 8 Log (cells g(-1) ), while the other were detected at 4 or 5 Log (cells g(-1) ). 86 Lactobacillus strains belonging to 52 species were identified. 43 seemingly occupied the GIT as true residents, since were detected in a time span of almost 2 years in all the three samples or in 2 samples separated by 670 or 700 d. As a whole, a stable community of lactobacilli was disclosed, with wide and understudied biodiversity.

Lactobacillus formosensis sp. nov., a lactic acid bacterium isolated from fermented soybean meal

A Gram-reaction-positive, catalase-negative, facultatively anaerobic, rod-shaped lactic acid bacterium, designated strain S215(T), was isolated from fermented soybean meal. The organism produced d-lactic acid from glucose without gas formation. 16S rRNA gene sequencing results showed that strain S215(T) had 98.74-99.60 % sequence similarity to the type strains of three species of the genus Lactobacillus (Lactobacillus farciminis BCRC 14043(T), Lactobacillus futsaii BCRC 80278(T) and Lactobacillus crustorum JCM 15951(T)). A comparison of two housekeeping genes, rpoA and pheS, revealed that strain S215(T) was well separated from the reference strains of species of the genus Lactobacillus. DNA-DNA hybridization results indicated that strain S215(T) had DNA related to the three type strains of species of the genus Lactobacillus (33-66 % relatedness). The DNA G+C content of strain S215(T) was 36.2 mol%. The cell walls contained peptidoglycan of the d-meso-diaminopimelic acid type and the major fatty acids were C18 : 1ω9c, C16 : 0 and C19 : 0 cyclo ω10c/C19 : 1ω6c. Phenotypic and genotypic features demonstrated that the isolate represents a novel species of the genus Lactobacillus, for which the name Lactobacillus formosensis sp. nov. is proposed. The type strain is S215(T) ( = NBRC 109509(T) = BCRC 80582(T)).

Fermented fruits and vegetables of Asia: a potential source of probiotics

As world population increases, lactic acid fermentation is expected to become an important role in preserving fresh vegetables, fruits, and other food items for feeding humanity in developing countries. However, several fermented fruits and vegetables products (Sauerkraut, Kimchi, Gundruk, Khalpi, Sinki, etc.) have a long history in human nutrition from ancient ages and are associated with the several social aspects of different communities. Among the food items, fruits and vegetables are easily perishable commodities due to their high water activity and nutritive values. These conditions are more critical in tropical and subtropical countries which favour the growth of spoilage causing microorganisms. Lactic acid fermentation increases shelf life of fruits and vegetables and also enhances several beneficial properties, including nutritive value and flavours, and reduces toxicity. Fermented fruits and vegetables can be used as a potential source of probiotics as they harbour several lactic acid bacteria such as Lactobacillus plantarum, L. pentosus, L. brevis, L. acidophilus, L. fermentum, Leuconostoc fallax, and L. mesenteroides. As a whole, the traditionally fermented fruits and vegetables not only serve as food supplements but also attribute towards health benefits. This review aims to describe some important Asian fermented fruits and vegetables and their significance as a potential source of probiotics.

Lactococcus formosensis sp. nov., a lactic acid bacterium isolated from yan-tsai-shin (fermented broccoli stems)

A coccal-shaped organism, designated 516T, was isolated from yan-tsai-shin (fermented broccoli stems), a traditional fermented food in Taiwan. 16S rRNA gene sequencing results showed that strain 516T had 98.9 % sequence similarity to that of the type strain Lactococcus garvieae NBRC 100934T. Comparison of three housekeeping genes, rpoA, rpoB and pheS, revealed that strain 516T was well separated from Lactococcus garvieae NBRC 100934T. DNA–DNA hybridization studies indicated that strain 516T had low DNA relatedness with Lactococcus garvieae NBRC 100934T (46.1 %). The DNA G+C content of strain 516T was 38.1 mol% and the major fatty acids were C16 : 0 (22.7 %), C19 : 0 cyclo ω8c (17.9 %) and summed feature 7 (29.0 %). Based on the evidence, strain 516T represents a novel species of the genus Lactococcus , for which the name Lactococcus formosensis sp. nov. is proposed. The type strain is 516T ( = NBRC 109475T = BCRC 80576T).

Enterococcus saccharolyticus subsp. taiwanensis subsp. nov., isolated from broccoli

A coccal strain isolated from fresh broccoli was initially identified as Enterococcus saccharolyticus ; however, molecular identification and phenotypic traits did not support this identification. DNA–DNA hybridization with the type strain of E. saccharolyticus (76.4 % relatedness), DNA G+C content (35.7 mol%), phylogenetic analysis based on 16S rRNA, pheS and rpoA gene sequences, rep-PCR fingerprinting and profiles of cellular fatty acids, whole-cell proteins and enzyme activities, together with carbohydrate metabolism characteristics, indicated that this strain is distinct and represents a novel subspecies, for which the name Enterococcus saccharolyticus subsp. taiwanensis subsp. nov. is proposed. The type strain is 812T ( = NBRC 109476T = BCRC 80575T). Furthermore, we present an emended description of Enterococcus saccharolyticus and proposal of Enterococcus saccharolyticus subsp. saccharolyticus subsp. nov. (type strain ATCC 43076T = CCUG 27643T = CCUG 33311T = CIP 103246T = DSM 20726T = JCM 8734T = LMG 11427T = NBRC 100493T = NCIMB 702594T).

Lactobacillus: host-microbe relationships

Lactobacilli are a subdominant component of the human intestinal microbiota that are also found in other body sites, certain foods, and nutrient-rich niches in the free environment. They represent the types of microorganisms that mammalian immune systems have learned not to react to, which is recognized as a potential driving force in the evolution of the human immune system. Co-evolution of lactobacilli and animals provides a rational basis to postulate an association with health benefits. To further complicate a description of their host interactions, lactobacilli may rarely cause opportunistic infections in compromised subjects. In this review, we focus primarily on human-Lactobacillus interactions. We overview the microbiological complexity of this extraordinarily diverse genus, we describe where lactobacilli are found in or on humans, what responses their presence elicits, and what microbial interaction and effector molecules have been identified. The rare cases of Lactobacillus septicaemia are explained in terms of the host impairment required for such an outcome. We discuss possibilities for exploitation of lactobacilli for therapeutic delivery and mucosal vaccination.

Lactococcus taiwanensis sp. nov., a lactic acid bacterium isolated from fresh cummingcordia

One coccal strain, designated 0905C15T, was isolated from fresh cummingcordia, which is the main ingredient of pobuzihi (fermented cummingcordia), a traditional fermented food in Taiwan. 16S rRNA gene sequencing results showed that strain 0905C15T had 98.22–98.82 % sequence similarity to that of the type strains of four Lactococcus lactis subspecies ( L. lactis subsp. lactis BCRC 12312T, L. lactis subsp. cremoris BCRC 12586T, L. lactis subsp. hordniae BCRC 80474T and L. lactis subsp. tructae BCRC 80475T). Comparison of two housekeeping genes, recA and rpoB, revealed that strain 0905C15T was well separated from the reference strains of the genus Lactococcus . DNA–DNA hybridization studies indicated that strain 0905C15T had low DNA relatedness to the four Lactococcus lactis subspecies (9.7–15.24 %). The DNA G+C content of strain 0905C15T was 39.6 mol %. Based on the evidence, strain 0905C15T represents a novel species of the genus Lactococcus , for which the name Lactococcus taiwanensis sp. nov. is proposed. The type strain is 0905C15T ( = NBRC 109049T = BCRC 80460T).

Draft Genome Sequence of Lactobacillus pobuzihii E100301T

Lactobacillus pobuzihii E100301^T is a novel Lactobacillus species previously isolated from pobuzihi (fermented cummingcordia) in Taiwan. Phylogenetically, this strain is closest to Lactobacillus acidipiscis, but its phenotypic characteristics can be clearly distinguished from those of L. acidipiscis. We present the draft genome sequence of strain L. pobuzihii E100301^T.

Isolation and characterisation of lactic acid bacteria from jiang-gua (fermented cucumbers), a traditional fermented food in Taiwan

BACKGROUND

Jiang-gua (fermented cucumbers) is a popular traditional fermented food in Taiwan. The microflora of lactic acid bacteria (LAB) in jiang-gua have not been investigated in detail. In this study, LAB from jiang-gua were isolated, characterised and identified.

RESULTS

A total of 103 LAB were isolated; 70 cultures were isolated from jiang-gua samples and 33 cultures were isolated from its raw substrate, cucumber. These isolates were mainly characterised phenotypically and then divided into seven groups (A-G) by restriction fragment length polymorphism analysis and sequencing of 16S ribosomal DNA. The isolates were identified as Enterococcus casseliflavus, Leuconostoc lactis, Leuconostoc mesenteroides, Lactobacillus pentosus, Lactobacillus plantarum, Lactobacillus paraplantarum, Lactococcus lactis subsp. lactis, Weissella cibaria and Weissella hellenica. The antibacterial activities of the isolates were determined and 11 Lc. lactis subsp. lactis strains showed inhibitory activity against the indicator strain Lactobacillus sakei JCM 1157(T) .

CONCLUSION

Heterofermentative W. cibaria and Leu. lactis were the major LAB found in jiang-gua samples without soy sauce. In soy sauce-added samples, homofermentative L. pentosus and L. plantarum were the most abundant LAB. In addition, the results also suggested that HhaI and RsaI restriction enzymes could be applied to distinguish W. hellenica and Weissella paramesenteroides.

Diversity of lactic acid bacteria in sian-sianzih (fermented clams), a traditional fermented food in Taiwan

BACKGROUND

Sian-sianzih (fermented clams) is a popular traditional fermented food in Taiwan. The lactic acid bacteria (LAB) microflora in sian-sianzih have not been studied in detail. In this study, LAB from sian-sianzih were isolated, characterized and identified.

RESULTS

A total of 186 cultures of LAB were isolated from seven sian-sianzih samples and 29 cultures were isolated from its main raw substrate: clams. The identification results revealed up to 11 distinct bacterial species belonging to five genera in sian-sianzih, and three species belonging to two genera in clams. The most common bacterial genera in sian-sianzih were Lactobacillus and Weissella, followed by Leuconostoc, Pediococcus and Lactococcus. A regional similarity in LAB, with differences in diversity, was observed in the current study. On the other hand, Lactococcus lactis subsp. lactis was the most common species found in raw clam samples. The results also suggested that greater LAB diversity could be observed in wild clams than in cultured ones. Furthermore, antibacterial activities of the isolates were determined, and one Weisella hellenica strain showed inhibitory activity against the indicator strain Lactobacilluas sakei JCM 1157(T) . A sensory assessment of seven sian-sianzih samples was also performed and the results indicated that diversity of LAB has a great effect on its aroma and taste formation.

CONCLUSION

The results demonstrate that various LAB species are distributed in sian-sianzih and have a great effect on the flavor of sian-sianzih.

Isolation and characterisation of lactic acid bacteria from yan-jiang (fermented ginger), a traditional fermented food in Taiwan

BACKGROUND

Yan-jiang (fermented ginger) is a popular traditional fermented food in Taiwan. The lactic acid bacteria (LAB) microflora in yan-jiang has not been studied in detail. In this study, LAB from yan-jiang were isolated, characterised and identified.

RESULTS

A total of 176 LAB were isolated; 160 cultures were isolated from yan-jiang samples and 16 cultures were isolated from raw ginger. These isolates were characterised phenotypically and then divided into nine groups (A to I) by restriction fragment length polymorphism analysis and sequencing of 16S ribosomal DNA. Lactobacillus sakei and Lactococcus lactis subsp. lactis were the major LAB found in the initial 2 days of fermentation without pickled plums; these species were mostly replaced by Weissella cibaria and L. plantarum after 3 days of fermentation. In the fermentation bucket with added pickled plums, W. cibaria was the most abundant LAB found during fermentation. The antibacterial activities of the isolates were determined. Twenty-four Lc. lactis subsp. lactis and 19 W. cibaria strains showed inhibitory activity against the indicator strain L. sakei JCM 1157(T) .

CONCLUSION

Results demonstrate that various LAB species were more numerous when fermentation was carried out without pickled plums. LAB also had effects on the aroma and flavour of yan-jiang.

Presence of sourdough lactic acid bacteria in commercial total mixed ration silage as revealed by denaturing gradient gel electrophoresis analysis

AIMS

To characterize the bacterial communities in commercial total mixed ration (TMR) silage, which is known to have a long bunk life after silo opening.

METHODS AND RESULTS

Samples were collected from four factories that produce TMR silage according to their own recipes. Three factories were sampled three times at 1-month intervals during the summer to characterize the differences between factories; one factory was sampled 12 times, three samples each during the summer, autumn, winter and spring, to determine seasonal changes. Bacterial communities were determined by culture-independent denaturing gradient gel electrophoresis. All silages contained lactic acid as the predominant acid, and the contents appeared stable regardless of factories and product seasons. Acetic acid and 1-propanol contents were different between factories and indicated seasonal changes, with increases in warm seasons compared to cool seasons. Both differences and similarities existed among the bacterial communities from each factory and product season. Lactobacillus parabuchneri was found in the products from three of four factories. Various sourdough lactic acid bacteria (LAB) were identified in commercial TMR silage; Lactobacillus panis, Lactobacillus hammesii, Lactobacillus mindensis, Lactobacillus pontis, Lactobacillus frumenti and Lactobacillus farciminis were detected in many products. Moreover, changes owing to product season were distinctive, and Lact. pontis and Lact. frumenti became detectable in summer products.

CONCLUSION

Sourdough LAB are involved in the ensiling of commercial TMR silage. Silage bacterial communities vary more by season than by factory. The LAB species Lact. parabuchneri was detected in the TMR silage but may not be essential to the product's long bunk life after silo opening.

SIGNIFICANCE AND IMPACT OF THE STUDY

Commercial TMR silage resembles sourdough with respect to bacterial communities and long shelf life. The roles of sourdough LAB in the ensiling process and aerobic stability are worth examining.