PENGARUH KONSENTRASI ONGGOK INDUSTRI TAPIOKA DAN UREA PADA PRODUKSI BIOHIDROGEN MELALUI FERMENTASI GELAP (INFLUENCE OF CONCENTRATION ONGGOK TAPIOCA INDUSTRY AND UREA IN BIOHYDROGEN PRODUCTION THROUGH DARK FERMENTATION) - Maghfiroh, Lailatul; Department of Chemistry, Faculty of Mathematics and Natural Sciences State University of Surabaya Jl. Ketintang Surabaya (60231), Telp. 031-8298761 (UNESA Journal of Chemistry, 2013)