CHARACTERIZATION OF LACTIC ACID BACTERIA FROM TRADITIONAL THAI FERMENTED SAUSAGES

Lactic acid bacteria from traditional Thai fermented sausages were characterized. The fermented sausages were mainly produced from minced pork/beef or pork/beef liver. Sixty five strains were isolated from 12 samples collected from the central and northeastern parts of Thailand. The strains were identified by conventional morphological, cultural, physiological and biochemical tests as well as by 16S rDNA sequence analysis. The isolates were identified as Weissella cibaria/kimchii (5), W. confusa (3), Pediococcus pentosaceus (20), P. acidilactici (2), Lactobacillus fermentum (3), L. brevis (4), L. farciminis (4), L. plantarum (23), and L. sakei (1). Some of these species have not been previously isolated from Thai fermented sausages. The inhibition tests against Bacillus cereus and Staphylococcus aureus showed that 5 isolates could inhibit the growth of B. cereus and 2 of them could also inhibit S. aureus. The isolates were identified as W. confusa (1), P. acidilactici (1), L. plantarum (3). Three strains identified as L. plantarum and one as Weissella spp. could produce diacetyl

Lipolytic and antimicrobial activities of Pseudomonas strains isolated from soils in Phetchaburi Province, Thailand

Purpose: To identify and determine lipolytic and antimicrobial activities, and  antibiotic susceptibility of bacterial isolates from soils in Phetchaburi Province, Thailand.Methods: Bacterial strains were isolated from surface soils by enrichment technique using lipolytic broth (LB) and then identified based on their phenotypic and genetic characteristics. The cell-free culture supernatant was determined for lipase activity by spectrophotometric assay. Disc diffusion assay was used to determine the crude ethyl acetate extract of the culture supernatant for antimicrobial activity and antibiotic susceptibility. The chemical profile of the crude ethyl acetate extract was analyzed by reverse-phase C-18 column high-performance liquid chromatography (HPLC).Results: On the basis of phenotypic properties and their 16S rRNA gene sequence analysis, five bacterial isolates, P1-2, P1-5, P1-6, P1-10 and P1-20 were identified as strains of Pseudomonas with sequence similarities (99.7 – 100 %). The extracellular lipase activity in LB supplemented with 1 % (v/v) of each of Tween 20, Tween 40, 60 or 80 as the substrate ranged from 11.61 ± 0.61 to 15.09 ± 0.42, 11.79 ± 0.28 to 15.75 ± 0.47, 12.65 ± 0.01 to 14.59 ± 0.87 and 12.71 ± 0.25 to 13.96 ± 0.21 unit/mL, respectively. The crude ethyl acetate extract of isolates P1-5, P1-6 and P1-20 contained quinoline alkaloid compounds and  exhibited antibacterial activity against Gram-positive Kocuria rhizophila ATCC 9341 and Staphylococcus aureus strains ATCC 25923, ATCC 6358 and ATCC 25913, but not against Gram-negative Escherichia coli ATCC 25922. All the  isolates were susceptible to cefepime, cefotaxime, ceftriaxone, ceftazidime,  amikacin, gentamicin, imipeneum, meropeneum and levofloxacin.Conclusion: The isolates demonstrate high lipolytic activity while the crude extracts exhibit antibacterial activity against Gram-positive bacteria. Thus, this lipase is a potential enzyme for pharmaceutical applications.Keywords: Antibiotic susceptibility, Antimicrobial activity, Lipolytic activity,  Pseudomonas, Thai soi

Characterization and screening of lipolytic bacteria from Thai fermented fish

Nine bacterial strains were isolated from Thai fermented fish by the standard dilution technique using JCM no. 377 medium. The rod shaped isolate FN2-3 was identified as Virgibacillus dokdonensis while isolates FN2-3 and FN6-6 as V. halodenitrificans, FN1-13 as Corynebacterium variabile, FN1-10 as Oceanobacillus iheyensis and FN3-7 was Bacillus amyloliquefaciens subsp. plantarum. The coccal isolates, FN6-1 and FN6-7 were Staphylococcus saprophyticus subsp. bovis and FN6-8 was S. saprophyticus subsp. saprophyticus, based on their phenotypic characteristics and 16S rRNA gene sequence analyses at a 99.63-100% sequence similarity. Their lipase activity in complex medium (CM), CM medium with 1% (v/v) Tween 20 or CM medium with 1% (v/v) Tween 80 ranged from 1.12 ± 0.03-3.77 ± 0.04 unit/mL, with the highest lipase activity found with V. dokdonensis FN1-8 cultivated with CM with 1% (v/v) Tween 80

Diversity and antimicrobial activity of the tropical ant-derived actinomycetes isolated from Thailand

Antibiotic resistance is one of the most important global healthcare challenges and is responsible for the mortality of millions of people worldwide every year. It is a crisis attributed to misuse of antibiotics and a lack of new drug development. Actinomycetes constitute a group of Gram-positive bacteria known for their distinctive high guanine-cytosine (G+C) content in their genomic DNA. These microorganisms are widely recognized for their capability to generate a wide range of secondary metabolites with diverse biological activities. These versatile microorganisms are ubiquitous in diverse ecosystems, including soil, freshwater, marine sediments, and within the bodies of insects. A recent study has demonstrated that social insects, such as ants, host a diverse array of these bacteria. In this study, we involved the isolation and characterization of a total of 72 actinomycete strains obtained from 18 distinct ant species collected from various regions across Thailand. Utilizing 16S rRNA gene analysis, these isolated actinomycetes were classified into four distinct genera: Amycolatopsis (2 isolates), Micromonospora (1 isolate), Nocardia (8 isolates), and Streptomyces (61 isolates). Among the Streptomyces strains, 23 isolates exhibited antimicrobial activity against a panel of Gram-positive bacteria, including Bacillus subtilis ATCC 6633, Staphylococcus epidermidis ATCC 12228, Staphylococcus aureus ATCC 25923, Kocuria rhizophila ATCC 9341, and Methicillin-resistant Staphylococcus aureus (MRSA) DMST 20646. Additionally, two isolates displayed antifungal activity against Candida albicans TISTR 5554. Based on 16S rRNA gene sequence similarity studies, these two isolates, ODS25 and ODS28, were demonstrated to be closely related to Streptomyces lusitanus NBRC 13464T (98.07%) and Streptomyces haliclonae DSM 41970T (97.28%), respectively. The level of 16S rRNA gene sequence similarity below 98.65% cutoff indicates its potential as a novel actinomycete species. These findings underscore the potential of actinomycetes sourced from ants as a valuable reservoir of novel antimicrobials

Production of 4-keto-D-arabonate by oxidative fermentation with newly isolated Gluconacetobacter liquefaciens

Production of 4-keto-D-arabonate (4KAB) was confirmed in a culture medium of Gluconacetobacter liquefaciens strains, newly isolated from water kefir in Argentina. The strains rapidly oxidized D-glucose, Dgluconate (GA), and 2-keto-D-gluconate (2KGA), and accumulated 2,5-diketo-D-gluconate (25DKA) exclusively before reaching the stationary phase. 25DKA was in turn converted to 4KAB, and 4KAB remained stable in the culture medium. The occurrence of 4KAB was assumed by Ameyama and Kondo about 50 years ago in their study on the carbohydrate metabolism of acetic acid bacteria (Bull. Agr. Chem. Soc. Jpn., 22, 271-272, 380-386 (1958)). This is the first report confirming microbial production of 4KAB.Centro de Investigación y Desarrollo en Fermentaciones Industriale

Production of 4-keto-D-arabonate by oxidative fermentation with newly isolated Gluconacetobacter liquefaciens

Production of 4-keto-D-arabonate (4KAB) was confirmed in a culture medium of Gluconacetobacter liquefaciens strains, newly isolated from water kefir in Argentina. The strains rapidly oxidized D-glucose, Dgluconate (GA), and 2-keto-D-gluconate (2KGA), and accumulated 2,5-diketo-D-gluconate (25DKA) exclusively before reaching the stationary phase. 25DKA was in turn converted to 4KAB, and 4KAB remained stable in the culture medium. The occurrence of 4KAB was assumed by Ameyama and Kondo about 50 years ago in their study on the carbohydrate metabolism of acetic acid bacteria (Bull. Agr. Chem. Soc. Jpn., 22, 271-272, 380-386 (1958)). This is the first report confirming microbial production of 4KAB.Centro de Investigación y Desarrollo en Fermentaciones Industriale

Comparative genomics reveals insight into the phylogeny and habitat adaptation of novel Amycolatopsis species, an endophytic actinomycete associated with scab lesions on potato tubers

A novel endophytic actinomycete, strain MEP2-6T, was isolated from scab tissues of potato tubers collected from Mae Fag Mai Sub-district, San Sai District, Chiang Mai Province, Thailand. Strain MEP2-6T is a gram-positive filamentous bacteria characterized by meso-diaminopimelic acid in cell wall peptidoglycan and arabinose, galactose, glucose, and ribose in whole-cell hydrolysates. Diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, and hydroxy-phosphatidylethanolamine were the major phospholipids, of which MK-9(H6) was the predominant menaquinone, whereas iso-C16:0 and iso-C15:0 were the major cellular fatty acids. The genome of the strain was 10,277,369 bp in size with a G + C content of 71.7%. The 16S rRNA gene phylogenetic and core phylogenomic analyses revealed that strain MEP2-6T was closely related to Amycolatopsis lexingtonensis NRRL B-24131T (99.4%), A. pretoriensis DSM 44654T (99.3%), and A. eburnea GLM-1T (98.9%). Notably, strain MEP2-6T displayed 91.7%, 91.8%, and 87% ANIb and 49%, 48.8%, and 35.4% dDDH to A. lexingtonensis DSM 44653T (=NRRL B-24131T), A. eburnea GLM-1T, and A. pretoriensis DSM 44654T, respectively. Based on phenotypic, chemotaxonomic, and genomic data, strain MEP2-6T could be officially assigned to a novel species within the genus Amycolatopsis, for which the name Amycolatopsis solani sp. nov. has been proposed. The type of strain is MEP2-6T (=JCM 36309T = TBRC 17632T = NBRC 116395T). Amycolatopsis solani MEP2-6T was strongly proven to be a non-phytopathogen of potato scab disease because stunting of seedlings and necrotic lesions on potato tuber slices were not observed, and there were no core biosynthetic genes associated with the BGCs of phytotoxin-inducing scab lesions. Furthermore, comparative genomics can provide a better understanding of the genetic mechanisms that enable A. solani MEP2-6T to adapt to the plant endosphere. Importantly, the strain smBGCs accommodated 33 smBGCs encoded for several bioactive compounds, which could be beneficially applied in the fields of agriculture and medicine. Consequently, strain MEP2-6T is a promising candidate as a novel biocontrol agent and antibiotic producer

Characterization of lactic acid bacteria from traditional Thai fermented sausages

Lactic acid bacteria from traditional Thai fermented sausages were characterized. The fermented sausages were mainly produced from minced pork/beef or pork/beef liver. Sixty five strains were isolated from 12 samples collected from the central and northeastern parts of Thailand. The strains were identified by conventional morphological, cultural, physiological and biochemical tests as well as by 16S rDNA sequence analysis. The isolates were identified as Weissella cibaria/kimchii (5), W. confusa (3), Pediococcus pentosaceus (20), P. acidilactici (2), Lactobacillus fermentum (3), L. brevis (4), L. farciminis (4), L. plantarum (23), and L. sakei (1). Some of these species have not been previously isolated from Thai fermented sausages. The inhibition tests against Bacillus cereus and Staphylococcus aureus showed that 5 isolates could inhibit the growth of B. cereus and 2 of them could also inhibit S. aureus. The isolates were identified as W. confusa (1), P. acidilactici (1), L. plantarum (3). Three strains identified as L. plantarum and one as Weissella spp. could produce diacetyl