Characterization of cellulase producing Bacillus and Paenibacillus strains from Thai soils.

Seventeen strains of cellulase producing bacteria were isolated from soil samples collected in Nan province, Thailand. They exhibited cellulase activity as a clear zone surrounded their colonies grown on carboxymethyl cellulose (CMC) agar medium ranged from 0.63 to 2.95 cm in diameter. Their hydrolysis capacity values were 1.65 - 7.55. The bacteria isolated were divided into 2 groups and belonged to genus Bacillus and Paenibacillus based on their phenotypic characteristics and chemotaxonomic characteristics such as meso-diaminopimelic in cell wall peptidoglycan and menaquinones of MK-7. Bacillus strains, P3-1 and P4-6 in Group I, produced maximum cellulase at 0.015 U ml-1. Their optimal pH and temperature for enzyme production and enzyme activity were 7.0 and 50 oC, respectively. The strains P3-1 and P4-6 were closely related to Bacillus velesensis LMG 22478T (100% similarity) whereas representative strain, S10-4 in Group II, was closely related to P. cellulositrophicus KCTC 13135T (98.7% similarity) based on 16S rRNA gene sequence. On the basis of their phenotypic, chemotaxonomic characteristics and phylogenetic analysis of 16S rRNA gene sequence, the strains P3-1 and P4-6 were identified as B. velesensis and the strain S10-4 was a novel species in the genus Paenibacillus.

Characterization and ethanol fermentation of Pichia and Torulaspora strains.

Seventy-two yeasts were isolated from sugarcane juices and sugar process-sediments collected in Thailand by incubated at 30 and 40oC in oxygen-limited condition. Six and eleven isolated yeasts produced ethanol with 0.46 and 0.22 g/g initial glucose at 30 and 40oC, respectively. The highest ethanol production efficacy, 0.30 g/g glucose of maximum ethanol yield at 40oC was found in isolates G1-4(1) and G1-12(3). On the basis of their phenotypic characteristics including the D1/D2 region of the large-subunit ribosomal (LSU) of 26S rRNA gene sequence analysis, the isolates G1-4(1) and G1-12(3) were identified as Pichia kudriavzvii and Torulaspora globosa, respectively.

Screening and characterization of protease-producing Virgibacillus, Halobacillus and Oceanobacillus strains from Thai fermented fish.

Halophilic bacteria from fermented fish (pla-ra and pla-chom), shrimp paste (ka-pi) and fermented crab] were isolated and screened for protease activities. Twenty-seven isolates exhibited protease specific activities ranged from 0.12 to 3.62 unit/mg protein. Isolate TPPN2-1 from pla-ra produced maximal protease specific activity (3.62 units/mg protein). They were Gram-positive, moderately halophilic rod-shaped bacteria and were divided into 5 groups on the basis of their phenotypic and chemotaxonomic characteristics, DNA-DNA relatedness including the 16S rRNA gene sequences analyses. Three isolates (Group I) were identified as Virgibacillus halodenitrificans, 3 isolates (Group II) as V. marismortui, 7 isolates (Group III) as V. dokdonensis, 10 isolates (Group IVA & IVB) as Halobacillus species and 4 isolates (Group V) as Oceanobacillus iheyensis.