Anaerobic flora, Selenomonas ruminis sp. nov., and the bacteriocinogenic Ligilactobacillus salivarius strain MP3 from crossbred-lactating goats.

This study aimed to examine the distribution of anaerobic bacteria in the rumen fluid of Thai crossbred goats and to screen potential probiotic strains capable of producing antimicrobial compounds and inhibiting bacteria that cause milk fat depression. Thirty-four strains of bacteria from the rumen fluid were divided into 13 groups within 12 genera based on 16S rRNA gene sequences. The RF1-5 and RF5-12 were identified as Streptococcus luteliensis and Bacillus licheniformis, respectively, and demonstrated non-ropy exopolysaccharide. Furthermore, mPRGC5T was closely related to Selenomonas caprae JCM 33725 T (97.8% similarity) based on 16S rRNA gene sequences. It exhibited low average nucleotide identity, digital DNA-DNA hybridization, and average amino acid identity values with related type strains ranging from 84.9 to 86.0%, 21.3 to 21.8%, and 73.8 to 76.1%, respectively. The genotypic and phenotypic characteristics of mPRGC5T strongly support this strain as a new species of the genus Selenomonas for which the name Selenomonas ruminis mPRGC5T was proposed. The type strain is mPRGC5T (= JCM 33724 T = KCTC 25177 T). Ligilactobacillus salivarius MP3 showed antibacterial activity against Cutibacterium acnes subsp. acnes DSM 1897 T and Kocuria rhizophila MIII. The enterolysin A cluster gene was identified in its genome. The auto-aggregation of L. salivarius MP3 was 93.6 ± 0.2%. Additionally, co-aggregation of L. salivarius MP3 with C. acnes DSM 1897 T and K. rhizophila MIII had 92.2 ± 3.4% and 87.3 ± 4.5%, respectively. The adhesion capacity of strain MP3 was 76.11 ± 2.2%. Probiogenomic analysis revealed that L. salivarius MP3 was nonhazardous to animal supplementation and included acid- and bile-tolerant ability. However, strain MP3 contained three antibiotic resistance genes. Thus, the supplementation of L. salivarius MP3 could increase the milk fat content by suppressing C. acnes DSM 1897 T with antibiotic resistance gene horizontal transfer awareness.

Development of a microencapsulated probiotic containing Pediococcus acidilactici WU222001 against avian pathogenic Escherichia coli.

Background and Aim: Probiotics are beneficial microorganisms for humans and animals. In this study, we developed a microencapsulated probiotic with antibacterial activity against avian pathogenic Escherichia coli (APEC). Materials and Methods: Alignment of the 16S rRNA sequences of the isolate WU222001 with those deposited in GenBank revealed that the isolate was Pediococcus acidilactici with 99.6% homology. This bacterium was characterized as a probiotic based on its tolerance toward in vitro gastrointestinal tract (GIT) conditions, hydrophobicity, and auto-aggregation. The antibacterial activity of the probiotic's culture supernatant against APEC was investigated using a broth microdilution assay. Pediococcus acidilactici was microencapsulated using sodium alginate and agar with diameters ranging from 47 to 61 µm. Then, physicochemical characteristics and stability of the microcapsules were determined. Results: The isolate was characterized as a probiotic based on its resistance to low pH, bile salts, and pancreatin, with relative values of 79.2%, 70.95%, and 90.64%, respectively. Furthermore, the bacterium exhibited 79.56% auto-aggregation and 55.25% hydrophobicity at 24 h. The probiotic's culture supernatant exhibited strong antibacterial activity against clinical APEC isolates with minimum inhibitory concentration and minimum bactericidal concentration of 12.5% and 25% v/v, respectively. Microencapsulation-enhanced bacterial viability in GIT compared to free cells. Moreover, 89.65% of the encapsulated cells were released into the simulated intestinal fluid within 4 h. The viable count in microcapsules was 63.19% after 3 months of storage at 4°C. Conclusion: The results indicated that the culture supernatant of P. acidilactici inhibited the growth of APEC. In addition, microencapsulation extends the viability of P. acidilactici under harsh conditions, indicating its potential application in the feed production.

Sporolactobacillus mangiferae sp. nov., a spore-forming lactic acid bacterium isolated from tree bark in Thailand.

A Gram-stain-positive, facultatively anaerobic and endospore-forming rod-shaped bacterium, designed strain CPB3-1T, was isolated from tree bark. This homofermentative strain produced dl-lactic acid from glucose. It grew at 20-45 °C, pH 4.0-9.5 and in 0-3.0 % (w/v) NaCl. It contained meso-diaminopimelic acid in cell-wall peptidoglycan and had menaquinone with seven isoprene units (MK-7) as the predominant component. The major fatty acid was anteiso-C17 : 0. The polar lipids were phosphatidylglycerol, diphosphatidylglycerol, an unknown phospholipid and an unknown lipid. Based on the results of 16S rRNA gene sequence analysis, strain CPB3-1T belonged to the genus Sporolactobacillus and was closely related to Sporolactobacillus kofuensis DSM 11701T and Sporolactobacillus spathodeae BK117-1T (both 96.7 % similarity), Sporolactobacillus inulinus NRIC 1133T and Sporolactobacillus terrae DSM 11697T (both 96.6 % similarity), and Sporolactobacillus shoreicorticis MK21-7T, Sporolactobacillus laevolacticus DSM 442T, Sporolactobacillus shoreae BK92T and Sporolactobacillus pectinivorans GD201205T (all 95.8-96.5 % similarity). The draft genome of strain CPB3-1T contained 2 930 919 bps with 3117 coding genes. The DNA G+C content was 45.1 mol%. The digital DNA-DNA hybridization values between strain CPB3-1T and closely related type strains were 19.2-24.0 %. The average nucleotide identity (84.0-87.6 %) and average amino acid identity (66.5-76.3 %) values were lower than the cut-off values for species delineation. Strain CPB3-1T was clearly distinguished from related Sporolactobacillus species based on its phenotypic and chemotaxonomic characteristics, 16S rRNA gene sequence similarity and the results of draft genome analysis. Therefore, the strain represents a novel species of the genus Sporolactobacillus, for which the name Sporolactobacillus mangiferae sp. nov. is proposed. The type strain is CPB3-1T (=JCM 35082T=TISTR 10004T).

Selenomonas caprae sp. nov., an obligately anaerobic and volatile fatty acid producing bacterium from ruminal fluid of domestic goat (Capra hircus L.).

A novel Gram-stain-negative, motile, obligately anaerobic bacterium strain mPRGC8T was isolated from the ruminal fluid of a domestic goat (Capra hircus L.) in Nakhon Pathom province, Thailand. The strain grew at 20-45 °C (optimum, 37 °C), pH 6.0-9.0 (optimum, pH 7.5) and 3 % (w/v) NaCl. It produced acetate, propionate, valerate, caproate and heptanoate from glucose. The 16S rRNA gene sequence analysis indicated that strain mPRGC8T belonged to the genus Selenomonas and was closely related to Selenomonas ruminantium subsp. ruminantium DSM 2150T (98.0 %) and Selenomonas ruminantium subsp. lactilytica JCM 6582T (97.9 %). The in silico DNA G+C content was 53.0 mol %. Strain mPRGC8T showed average nucleotide identity, digital DNA-DNA hybridization and average animo acid identity values with Selenomonas montiformis JCM 34373T, S. ruminantium subsp. lactilytica JCM 6582T and S. ruminantium subsp. ruminantium DSM 2150T ranging from 84.9 to 86.0 %, 21.3 to 21.8 % and 73.8 to 76.1 %, respectively. The predominant cellular fatty acids were C16 : 1 ω9c and C18 : 1 ω9c. Phosphatidylethanolamine, three unidentified aminophospholipids, two unidentified ninhydrin positive glycolipids, an unidentified phospholipid and an unidentified lipid were detected as polar lipids. The genomic and phenotypic characteristics of strain mPRGC8T strongly support its classification as representative of new species of the genus Selenomonas for which the name Selenomonas caprae sp. nov. is proposed. The type strain is mPRGC8T (=JCM 33725T=KCTC 25178T).

Draft genome sequencing data of the moderately halophilic bacterium, Allobacillus halotolerans SKP2-8 from shrimp paste (ka-pi).

A moderately halophilic, Gram-stain-positive, spore-forming rod-shaped bacterium, designated SKP2-8 was isolated from a traditional fermented shrimp paste (Ka-pi) collected from the market in Samut Sakhon province, Thailand. This isolate SKP2-8 was closely related to Allobacillus halotolerans LMG 24826T with 99.56% similarity based on 16S rRNA gene sequence. The draft genome of SKP2-8 was 2.53 Mb with 2,515 coding sequences with an average G+C content of 39.5 mol%. The ANIb, ANIm, AAI and the digital DNA-DNA hybridization values of isolate SKP2-8 were 97.22%, 97.64%, 97.75% and 78.0%, respectively, compared with A. halotolerans LMG 24826T. Based on the phenotypic characteristics, DNA-DNA relatedness and phylogenomic analysis, it was identified as Allobacillus halotolerans. The genome sequence data of this isolate provide information for further analysis of the potential biotechnological use of this microorganism and guide the characterization. The draft genome was deposited at DDBJ/ EMBL/GenBank (DNA Databank of Japan/European Molecular Biology Laboratory/Genbank) (VMHF00000000).