Browsing by Author "Jirapa Phetsom"
Results Per Page
ItemIsolation and purification of cellulase from alkaline-tolerant Bacillus subtilisLignocellulosic biomass is one of the most abundant renewable resource in the world. It has high potential to be used as material for biorefinery process because it yields fermentable sugar that can be converted to various bioproducts via microorganism functions. To make the biorefinery process success, the efficient hydrolysis process is needed to be improved to release the maximum amounts of sugars from lignocellulosic biomass. Natural environment is an important source to find an efficient cellulase producing bacteria. Previously, an alkaline-tolerant cellulase-producing bacterium, Bacillus subtilis strain MSB9, was screened and isolated from Botanic garden in Mahasarakham province, Thailand. In this study, we focused on the purification and characterization of cellulase enzyme produced by B. subtilis strain MSB9. The crude cellulase enzyme was partially purified and concentrated by ammonium sulfate precipitation and fractionated by using size exclusion chromatography using sephacryl S-100 HR column. Two of purified cellulase have relative molecular mass of 35 and 45 kDa, as determined by SDS-PAGE combined with CMC-zymogram.
ItemA study of feasibility of pretreatment process to utilize lignocellulosic biomass as materials for biodiesel productionBiomass is the most abundant renewable resource in the world and has potential to use as alternative materials to fossil resources for production of chemicals and fuels. For the effective conversion from biomass to biofuels or other chemicals, it requires high efficient hydrolysis of cellulose to glucose or fermentable sugars. In this study, lignocellulosic biomass, rice straw, rice husk, and water hyacinth were pretreated with different chemicals, or pretreated with microwave heating, or with combination of chemicals and microwave heating. Pretreated biomass was saccharified by using commercial cellulase enzymes and released sugar contents were measured. The combination of two pretreatment methods exhibited a synergy effect with 71.77% of the enzymatic sugar conversion. To study the possibility to utilize sugars from saccharified biomass, the de novo biosynthesis of fatty acid ethyl esters (FAEEs) in Acinetobacter spp were observed. The key biochemical reaction is the esterification between fatty acyl Co-A and ethanol using diacylglycerol acyltransferase (DGAT). The highest FAEE production up to 1,040±51 mg/l was found in A.baylyi culture that use biomass hydrolysate as a sole carbon source.