Enhancement of Biogas Production from Rice Husk by NaOH and Enzyme Pretreatment Syafrudin, Winardi Dwi Nugraha, Shandy Sarima Agnesia, Hashfi Hawali Abdul Matin and Budiyono E3S Web Conf., 31 (2018) 02002 Published online: 21 February 2018 DOI: 10.1051/e3sconf/20183102002