This study aimed to isolate and identify bacteria that can produce amylase enzyme from the unexplored Nasinuan Forest, Kantarawichai District, Mahasarakham Province, Thailand. Thirteen bacterial isolates with amylase-producing capacity on 1% starch agar were identified using 16S rRNA sequencing. Twelve bacteria were gram-positive, rod shaped and identified as Bacillus spp. and one bacterium with gram-negative and rod shaped character was Enterobacter cloacae. Their closest relatives were found in India, China, Korea, Indonesia, Argentina, Italy, Israel, USA, Argentina and South Africa. These bacteria were tested for specific amylase activity after 1-3 days enzyme induction with 1% starch at 37°C. The results showed the highest specific activity at day 2 incubation in the order: Bacillus cereus 3.5AL2 > 3.4AL1 > 1.4AL3 and thus 2-day enzyme induction was chosen for further analysis. Bacillus sp. 3.5AL2 was found to exhibit the highest specific amylase enzyme activity of 1.97 ± 0.41 U/mg protein at the optimal conditions of 60°C and pH 7.0 after 30 min incubation with 1% starch in 0.05 M PBS buffer. This amylase–producing bacterial strain offers great potential for applications in food and agricultural industries in Thailand.

The aims of this novel work were to determine the microbial strains and exopolysaccharide (EPS) producers in water kefir from Nakhon Ratchasima Province, Thailand. Thirty-three microbial strains were identified using 16S rRNA gene analysis consisting of 18 bacterial strains, as 9 strains of acetic acid bacteria (AAB), 9 strains of lactic acid bacteria (LAB), and 15 yeast strains. All bacteria were able to produce EPS with a diverse appearance on agar media containing different sugars at a concentration of 8%. Culture supernatants from AAB and LAB showed 31−64% 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity with the highest antioxidant activity of 64% from Acetobacter pasteurianus WS3 and WS6. Crude EPS from A. pasteurianus WS3 displayed the highest ferric reducing antioxidant power at 280 mM FeSO 4 /g EPS, greatest anti-tyrosinase activity at 20.35%, and highest EPS production of 1,505 mg EPS/L from 8% sucrose. These microbes offer beneficial health implications and their EPSs can be used as food additives and cosmetic ingredients.

The current work aimed to screen for and identify protease-producing bacteria from the untapped resource Nasinuan forest, Kantarawichai District, Mahasarakham Province, Thailand. Nineteen bacterial isolates with protease-producing capacity on 1% skimmed milk agar were identified using 16S rRNA sequencing. Seventeen bacteria were gram-positive, rod shaped and identified as Bacillus spp. and only two bacteria were identified as Enterobacter sp. and Staphylococcus cohnii. Their closest relatives were found in India, Oman, Italy, Indonesia, Malaysia, China and USA. The top six highest halo : colony ratios from pure isolates were ranked in the following order: 1.2PT1 (2.43) > 1.2PT2 (2.23) > 2.2PT3 (2.21) > 2.1PT3 (2.17) > 2.3PT3 (2.16) > 2.4PT1 (2.16). Bacillus thuringiensis 2.3PT3 was found to exhibit the highest protease enzyme activity of 3.72 ± 0.08 U/mg protein at the optimal conditions of 65°C and pH 8.0 after 30 min incubation with 1% casein in 0.05 M PBS buffer. This protease–producing bacterial strain can be of great potential for applications in food, agricultural and pharmaceutical industries in Thailand.