Optimization of pH, water content, and temperature on the in vitro biodelignification of oil palm empty bunches

English. Oil palm empty bunches (OPEB) is a solid waste product of palm oil industrial processing. OPEB consists of cellulose which has potential as a raw material for pulping. Biodelignification is part of the pulping processes facilitated by microorganism such as white-rot fungi which are capable for degrading lignin. The aim of this research was to determine the optimum pH of the initial process, water content, and temperature for the biodelignification of OPEB. Biodelignification was carried out through solid-state fermentation using 5 percent inoculum of white-rot fungus K14 in an Erlenmeyer flack at pH 3.5-5.5, 30-70 percent moisture content, and 28-48 deg. C temperature. Analyses carried out consisted of determination for lignin, cellulose, and hemicellulose content. The optimum condition for biodelignification was selected on the basis of lowest lignin-cellulose ratio. The results showed that the optimum water content for the growth of the white rot fungus was 50-70 percent. Beside lignin, the concentrations of cellulose and hemicellulose decreased during the growth of the fungus. The optimum condition for biodelignification was obtained after 30 days of incubation at temperature 28 deg. C, pH of 3.5 and water content of 50 percent with a lignin-cellulose ratio of 0.28, compared to the control having a lignin-cellulose ratio of 0.37. There was no significant effect of pH and water content on the lignin-cellulose ratio

Indonesian. Tandan kosong kelapa sawit (TKKS) adalah suatu limbah padat dari industri pengolahan minyak sawit. TKKS tersusun atas selulosa yang berpotensi untuk digunakan sebagai bahan baku pulp. Biodelignifikasi merupakan bagian dari proses pulping dengan bantuan mikroorganisme seperti fungi pelapuk putih yang mampu mendegradasi lignin. Tujuan penelitian adalah mengetahui pH awal proses, kadar air, dan suhu optimum untuk biodelignifikasi TKKS. Biodelignifikasi dilakukan melalui metode fermentasi fase padat menggunakan 5 persen inokulum kapang pelapuk putih K14 dalam labu Erlenmeyer pada pH 3,5-5,5, kadar air 30-70 persen, dan suhu 28-48 derajat Celcius. Analisis yang dilakukan meliputi kadar lignin, selulosa, dan hemiselulosa. Kondisi optimum dipilih berdasarkan rasio lignin-selulosa terendah. Hasil penelitian menunjukkan bahwa kadar air optimum untuk pertumbuhan kapang pelapuk putih tersebut adalah 50-70 persen. Di samping lignin, selulosa dan hemiselulosa berkurang kadarnya selama pertumbuhan kapang. Kondisi optimum biodelignifikasi diperoleh pada inkubasi 30 hari pada suhu 28 derajat Celcius, pH 3,5 dan kadar air 50 persen dengan ratio lignin selulosa 0,28, dibanding kontrol yang memiliki rasio lignin-selulosa sebesar 0,37. Tidak ada pengaruh nyata pH dan kadar air terhadap rasio lignin-selulosa