Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XX
Written by RATU SAFITRI, ATHENA DINANTY, GUSTAN PARI, MOH. NURZAMAN
The purpose of this study was to obtain effective dose of hydrolase enzyme (α-amylase, hemicellulase, cellulase and amyloglucosidase) to produce highest levels of reducing sugars and dextrose equivalent (DE), and also to obtain the best microbial consortium in the fermentation of cellulose from pulp waste to produce bioethanol. This research used descriptive and experimental methods. The descriptive method was used in the optimization of hydrolase enzyme dosage, while the experimental method was used in cellulose of reject pulp fermentation. Parameters used in this study consist in ethanol content, reducing sugar content, microbial population and DE. Our results showed that the highest levels of reducing sugars in the optimization process of α-amylase enzyme was obtained at a dose of 0,52 μL g-1 whereas hemicellulase enzyme was at a dose of 2/3 or 0.00067 g g-1 and cellulase as well as amyloglucosidase was at a dose of 1 + 1 or 0.83 μL g-1 and 0,56 μL g-1, respectively. Additionally, the most effective and optimum fermentation was obtained by a consortium of Kluyveromyces marxianus and Zymomonas mobilis (K2), with ethanol content and fermentation efficiency as much as 6.27 and 59.48%, respectively. High levels of ethanol produced was also supported by the lowest reducing sugar content of 1.32% with the average of DE 1.69. Moreover, ethanol yield (Yp/s), maximum specific ethanol productivity (qp) and cell yield (Yx/s) were also obtained at 21, 76 and 26%, respectively. We observed that consortium K. marxianus and Z. mobilis (K2) reached the highest logarithmic phase at 36th hour, with a population of 11,80x1010 cfu mL-1.
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