Int. J. Biosci.18(4), 101-110, April 2021
Agricultural Biomass are abundant and potential alternative for fossil fuels in Mindanao, Philippines. However, biomass contains lignocellulose that is recalcitrant to enzymatic hydrolysis because of its structural complexity. As a solution, pH controlled liquid hot water (LHW) and Ultrasonic pretreatment of cellulosic feedstock is employed in order to improve its enzymatic digestibility and making the cellulose more accessible to cellulase enzymes. The LHW pretreatment is carried out by cooking the feedstock using autoclave at temperatures between 160 and 190 degrees C and at a pH of 4-7. An additional 3-4% w/v Sodium Hydroxide solution is deployed to further improve its enzymatic digestibility. This resulted in an increase of methane production up to 300% more due to the pretreatment of rice straw and coconut shells. Further, the pretreated coconut shell subjected to Ultrasonication with 3% NaOH and Liquid Hot water has the best effect among the pretreatment of biomass feedstocks of rice straw and coconut shell at certain NaOH concentrations. This would give a viable estimate on the possible methane production from the co-digestion of these resources. Also, the enhancement of the biogas yield was mainly attributed to the improvement of biodegradability of rice straw and coconut shells through these pretreatments. The changes in chemical compositions, chemical structures, and physical characteristics made rice straw and coconut shell feedstocks become more available and biodegradable and thus were responsible for the enhancement of the biogas yield. These results are contributing to develop a feasible biogas production from rice straw and coconut shell.
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