Lactic acid bacteria (LAB) are significant groups of probiotic organisms in fermented food and are generally considered safe. LAB regulate soil organic matter and the biochemical cycle, detoxify hazardous chemicals, and enhance plant health. They are found in decomposing plants, traditional fermented milk products, and normal human gastrointestinal and vaginal flora. Exploring LAB identified in unknown niches may lead to isolating unique species. However, their classification is quite complex, and they are adapted to high sugar concentrations and acidic environments. LAB strains are considered promising candidates for sustainable agriculture, and they promote soil health and fertility. Therefore, they have received much attention regarding sustainable agriculture. LAB metabolites promote plant growth and stimulate shoot and root growth. As fertilizers, LAB can promote biodegradation, accelerate the soil organic content, and produce organic acid and bacteriocin metabolites. However, LAB show an antagonistic effect against phytopathogens, inhibiting fungal and bacterial populations in the rhizosphere and phyllosphere. Several studies have proposed the LAB bioremediation efficiency and detoxification of heavy metals and mycotoxins. However, LAB genetic manipulation and metabolic engineered tools provide efficient cell factories tailor-made to produce beneficial industrial and agro-products. This review discusses lactic acid bacteria advantages and limitations in sustainable agricultural development.

A novel isolate, designated 6408J-67^T, was isolated from an air sample collected from Jeju Island, Republic of Korea. Its phenotypic, genotypic, and chemotaxonomic properties were compared with those of members of the family Microbacteriaceae. The Gram-positive, aerobic, motile rod formed light yellow, smooth, circular and convex colonies. Optimal growth occurred at 30°C and pH 7.0. 16S rRNA gene sequence data showed that the isolate was a novel member of the family Microbacteriaceae, with the highest sequence similarity (97.4%) to Labedella gwakjiensis KSW2-17^T and less (10% of the total) were anteiso-C_15:0, iso-C_14:0, and iso-C_16:0. The strain also contained MK-13, MK-12, and MK-14 as the major menaquinones, as well as diphosphatidylglycerol, phosphatidylglycerol, and two unknown glycolipids. Its peptidoglycan structure was B1β with 2,4-diaminobutyric acid as a diamino acid. Mycolic acids were absent. The DNA G+C content was 68.3 mol%. Based on these phenotypic and genotypic findings, strain 6408J-67^T represents a novel species of a new genus within the family Microbacteriaceae, for which the name Diaminobutyricimonas aerilata gen. nov., sp. nov. is proposed. The type strain is 6408J-67^T (=KACC 15518^T =NBRC 108726^T).

Jegadeesh Raman, Jun Su Noh, Jeong-Seon Kim, Gyeongjun Cho, Do-Hyun Kim, Jaekyung Song, and Soo-Jin Kim. J. Microbiol. Biotechnol. 2025;35:1-14. https://doi.org/10.4014/jmb.2507.07043

A bacterial strain designated 5GH32-13^T was isolated from greenhouse soil in Yongin-city, Republic of Korea. Cells were Gram-stain-negative, strictly aerobic, motile rods of two different shapes. The strain was catalase-positive and oxidase-negative. Flexirubin-like pigments were not detected. β-Carotene was produced. The strain grew in the range of 10–37°C (optimum of 28–30°C) and pH 6–8 (optimum of pH 7) and tolerated up to 1% (w/v) NaCl (optimum of 0%). According to the 16S rRNA gene sequence comparison, strain 5GH32-13^T shared a sequence similarity of less than 96.0% with all validly named taxa, having the highest sequence similarity with Pseudoflavitalea soli KIS20-3^T (95.8%), Pseudoflavitalea rhizosphaerae T16R-265^T (95.4%), Flavitalea gansuensis JCN-23^T (95.3%), Pseudobacter ginsenosidimutans Gsoil 221^T (95.3%), and Flavitalea populi HY-50R^T (95.2%). A phylogenetic tree showed that strain 5GH32-13^T was not grouped consistently into any specific genus. Its only polyamine was homospermidine, and its major fatty acids (> 10% of total fatty acids) were iso-C_15:0, iso-C_17:0 3-OH, and iso-C_15:1 G. The strain’s only respiratory quinone was MK-7, and its polar lipids were phosphatidylethanolamine, one unidentified phospholipid, six unidentified aminolipids and four unidentified lipids. Its DNA G + C content was 47.5 mol%. The results from chemotaxonomic, phenotypic and phylogenetic analyses indicated that strain 5GH32-13^T represents a novel species of a novel genus of the family Chitinophagaceae, and the name Paraflavitalea soli gen. nov., sp. nov. is proposed. The type strain is 5GH32-13^T (= KACC 17331^T = JCM 33061^T).

An actinobacterial strain, designated FW100M-8T, was isolated from a gut sample of larva of Protaetia brevitarsis seulensis at the National Institute of Agricultural Sciences, Wanju-gun, South Korea. Cells were Gram-stain-positive, microaerophilic to aerobic, non-spore forming and non-motile. It grew at pH 7.0–9.0 (optimum, pH 8.0), at 15–35 °C (optimum, 28 °C) and 0–3.0 % (w/v) NaCl (optimum, 0 %). According to the 16S rRNA gene analysis, strain FW100M-8T shared the highest sequence similarity with Agromyces mediolanus DSM 20152T (98.4 %), Agromyces ulmi XIL01T (98.3 %), Agromyces indicus NIO-1018T (98.3 %), Agromyces soli MJ21T (98.3 %), and Agromyces arachidis AK-1T (97.9 %). Phylogenetic trees showed that strain FW100M-8T fell into the lineage of the genus Agromyces . The polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, an unidentified glycolipid and an unidentified lipid. The menaquinones of strain FW100M-8T were MK-12 (46 %), MK-11 (36 %), MK-10 (14 %) and MK-13 (4 %). The major fatty acids were anteiso-C15 : 0, anteiso-C17 : 0 and iso-C16 : 0. The peptidoglycan type was supposed to be the type B1, comprising d-Ala, d-Glu, Gly and l-A2bu. The G+C content of the genomic DNA is 70.5 mol%. On the basis of the genotypic and phenotypic data, we conclude that strain FW100M-8T represents a novel species of the genus Agromyces , for which the name Agromyces protaetiae sp. nov. is proposed with strain FW100M-8T (=KACC 19308T=NBRC 113048T) as the type strain.

A rod-shaped, Gram-stain-positive, non-flagellated, facultatively anaerobic bacterium, designated SYF10-1aT, was isolated from Nuruk, a Korean traditional fermentation starter. It grew at 4–40 °C (optimum 37 °C), at pH 3.0–9.0 (optimum, pH 7.0) and with 0–5 % (w/v) NaCl. Phylogenetic analysis using 16S rRNA gene sequences revealed that strain SYF10-1aT belonged to the genus Lactobacillus and showed the highest sequence similarity of 98.7 % to Lactobacillus crustorum LMG 23699T. A comparison of two housekeeping genes, pheS and rpoA, supported the suggestion that strain SYF10-1aT fell within the radius of the genus Lactobacillus , but was clearly separated from its closest related species. The average nucleotide identity value and digital DNA–DNA hybridization value between strain SYF10-1aT and the most closely related species, L. crustorum LMG 23699T, were 80.5 and 33.3 %, respectively. The predominant cellular fatty acids were C16 : 0, C18 : 1ω9c, C18 : 1ω7c and summed feature 3 (including iso-C15 : 0 2-OH and/or C16 : 1ω7c). Polar lipids were diphosphatidylglycerol, phosphatidylglycerol, two unidentified aminolipids and two unidentified glycolipids. The cell-wall peptidoglycan was of the A4α type with an interpeptide bridge comprising l-Lys-d-Asp. The DNA G+C content was 34.2 mol%. On the basis of this taxonomic study, strain SYF10-1aT represents a novel species within the genus Lactobacillus , for which the name Lactobacillus nuruki sp. nov. is proposed. The type strain is SYF10-1aT (=KACC 18726T=NBRC 112011T).