The effects of pretreatment time and acid hydrolysis concentration on biothanol production from Eucheuma denticulatum (N.L. Burman) Collins & Hervey / Nur Asyiqin Yunos

Increasing demand on energy resources and concerns towards greenhouse emissions cause attraction on studies toward biofuels production as it is essential for transportation and as sustainable sources of renewable energy. The objectives of this study is to determine the chemical constituent of Eucheuma denticulatum primary metabolites, evaluate pretreatment methods including chemical and heat pretreatment and different acid hydrolysis concentration in production of reducing sugar, and finally evaluation of different concentration of acid hydrolysis for optimization of bioethanol production. The methods used to estimate reducing sugar and bioethanol content were standard physicochemical composition that consists of moisture, carbohydrate and lipid content, phenol sulphuric acid test for reducing sugar estimation and solvent extraction and dichromate oxidation for estimation of bioethanol yield. The result for Eucheuma denticulatum physicochemical analyze are moisture content is 34.67%, carbohydrate content is 23.23% which is higher than lipid content of 5.3%. The result for highest production of reducing sugar for Eucheuma denticulatum is 285.7 mg/ml which produce the highest yield of bioethanol of 7.12% with the best optimization method of 0.4 M sulphuric acid for acid hydrolysis at 25 minute autoclave time (AT) as pretreatment time. This result proves that Eucheuma denticulatum has potential as biomass for bioethanol production and reducing sugar produced that has positive correlation to bioethanol yield. It is recommended to do the analysis on inhibitory product 5-HMF during chemical and heat pretreatment and apply detoxification method to degrade the inhibitory product in order to produce higher yield of bioethanol for Eucheuma denticulatum.