초록
<P><B>Abstract</B></P> <P>Palm oil mill effluent (POME) is well known as the potential raw material for biogas production. However, the high hemicellulose and cellulose content (10–14% w/w in dry basis) of the palm fibre in POME are less accessible for biodegradable to sugars, therefore, limiting the carbon source for microorganisms for the biogas production. This study attempted to enhance the hydrolysis step of the biomass by enzymatic pretreatment of POME. The optimum temperature and hydrolysis time using the commercial xylanase (5 unit/mL) were at 50 °C for 12 h. Two-steps thermophilic process consisting of POME pretreatment by various concentrations of xylanase (5–20 unit/mL) under the optimum condition followed by biogas production at 60 °C for 45 days was carried out. In all cases, the substrate to inoculum volatile solids (VS) ratio and volume ratio were 1:1 and 4:1, respectively. The maximum biomethane (CH<SUB>4</SUB>) yield of 914 mL CH<SUB>4</SUB>/g VS was obtained from the fermentation of POME hydrolysed by 15 unit/mL of xylanase. However, it was not significantly different from those of the other three concentrations of xylanase (845, 870 and 851 mL CH<SUB>4</SUB>/g VS, respectively). They were about 2.5–3 folds higher than that of the control (POME without enzymatic hydrolysis) (297 mL CH<SUB>4</SUB>/g VS). Microbial community analysis revealed the presence of <I>Clostridium</I> sp. and <I>Methanocaldococcus</I> sp. as the dominant strains.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The hydrolysis step in anaerobic digestion was enhanced by addition of xylanase. </LI> <LI> The optimum condition for enzymatic hydrolysis was at 50 °C for 12 h. </LI> <LI> Glucose and xylose concentration in POME hydrolysate increased 5.3 and 15.6 folds, respectively, compared to raw POME. </LI> <LI> Enzymatic hydrolysis of POME could increase biogas yield by 3 folds. </LI> <LI> Microbial community contained <I>Clostridium</I> sp. and <I>Methanocaldococcus</I> sp. </LI> </UL> </P>