Application of Subcritical Water Hydrolysis (SCW) in Producing Reducing Sugar for Biofuel Production

Dian Ranggina (Politeknik Negeri Ujung Pandang)
Maria Assumpta Nogo Olea (Department of Chemical Engineering, Ujung Pandang State Polytechnic, Makassar, Indonesia)
Hanny F. Sangian (Department of Physics, Sam Ratulangi University, Manado, Indonesia)
Arief Widjaja (\Department of Chemical, Engineering Institut Teknologi Sepuluh Nopember, Surabaya, Indonesia)
Hijrah Amaliah Azis (Department of Chemical, Faculty of Engineering, Sulawesi University of Technology, Indonesia)

Equilibrium Journal of Chemical Engineering
Vol 8, No 2 (2024): Volume 8, No 2 December 2024--Online First

Abstract. This work aimed to produce reducing sugar from coconut husk using subcritical water hydrolysis. Coconut husk contains cellulose and hemicellulose that can be converted into reducing sugars and then fermented into biofuel. In this study, the subcritical water hydrolysis was carried out in a batch reactor at  temperatures 120-260 oC and pressures, 40, 80, and 160 bar for 1 h. Subcritical water method obtained two products, namely (a) liquid containing sugar and (b) solid containing cellulose, hemicellulose and lignin. The liquid sugars were analyzed by HPLC and DNS, while crystal structure was characterized by XRD and SEM. The highest yield of reducing sugar obtained was 0.25 g/g cellulose+ hemicellulose at 150 oC and 80 bar.Keywords: Biofuel, Coconut husk, Lignocellulose, Reducing sugar, Subcritical water