Rekayasa proses produksi hidrolisat dari ampas sagu sebagai substrat untuk pembuatan bioetanol

Abstract

Sago hampas is one abundant biomass available in Indonesia, because Indonesia has more than half (56.5%) of world sago forest. The research objective was to obtain a high sugar hydrolysate from sago hampas, as a substrate for production of bioethanol. The study was done in four phases: 1) Analysis of sago hampas biomass and its pretreatment, 2) Hydrolysis of sago hampas starch using hydrothermal enzymatic method and using 0.25 M H2SO4 solution as a comparison, 3) Conversion of sago hampas cellulose into glucose using Trichoderma reesei, and 4) Application of hydrolysate from sago hampas for bioethanol production and its added value analysis. Results showed that the largest contain of sago hampas was starch followed by cellulose. Pretreatment of sago hampas using distilled water at 115 oC for 15 minutes gave the highest starch content of 17.98 g/L (the yield of 87.24%). In the other hand, treatment with 0.25 M H2SO4 at 115 oC for 15 minutes gave the highest total sugar at 20.23 g/L in the extract (88.16% conversion factor). Sago hampas starch in extract was then converted by enzymatic method to sugar with the highest dextrose equivalent result of 86.56%. Conversion of sago hampas cellulose into glucose was carried out by Trichoderma reesei in Erlenmeyer flask using water bath shaker, resulting in 0.3 g/L glucose. Glucose produced seems to be repressor for further cellulase production, which is known as glucose effect. Bioethanol concentration obtained from sugar hydrolysate using hydrothermal enzymatic method was slightly higher compared to bioetanol concentration obtained using 0.25 M H2SO4 method, i.e 2.82% and 2.65% respectively. Added value obtained from sago hampas hydrolysate production using hydrothermal enzymatic method with cellulose residue as by-product was about Rp. 444.79 for each kg of output with 41.54% of added value ratio. Production factor compensation for businnes owner, worker and other input price were 41.06%, 7.25% and 51.69% respectively.