Lignocellulosic Wastes Degradation without Pretreatment by Thermo cellulolytics Bacteria Isolated from Hot Spring in Southern Thailand. Cellulase GH5 gene

The new generation of ethanol production, mostly obtained from the conversion of cellulose from agriculture waste residues. Cellulase is able degrade cellulose to glucose. Genus Geobacillus is gram-positive thermophile, can express and produced various types of thermostable glycoside hydrolases for cellulose degradation. Geobacillus strain PK12 isolated from Pakpoo hot spring showed growth at temperature range between 40 – 70 ˚C (Topt 65 ˚C) and pH range between 6 -8 (pHopt8). The DNA-DNA hybridization analysis of strain PK12 with its closest phylogenetic neighbor Geobacillus thermoleovorans found to be only 64% with indicate novel species (< 70%). The cellulase enzyme produced by Geobacillus sp. PK12 (bgl-G12) belongs to glycoside hydrolase family 5 and CBM X2. The molecular weight of purified cellulase was 72 kDa. The optimal activity at 55°C and pH 5.0 and was completely stable. Geobacillus sp. PK12 has highest xylanase, CMCase and avicelase of 0.19, 0.2 and 0.25 U/mL.