Effects of yeast extract and peptone on hydrolysed sago stratch for bioethanol production

The subject of this study was the effect of yeast extract and peptone on production of glucose and ethanol productivity from hydrolysed sago starch (HSS) (100 g/L) using Saccharomyces cerevisiae. Since there are none nitrogen content was observed in sago starch, thus supplementation of nitrogen sources in the media are important. The method used was batch fermentation HSS with 100 mL initial volume with each was supplemented with nitrogen sources (yeast extract and peptone) and was maintained at room temperature (30 'C ± 0.5). The initial pH was set around 5.5-5.6 and fermentation was conducted in incubator shaker for 24 hours. Commercial glucose was used as control sample to compare it with HSS. In comparison of HSS with control sample, the gradual increase in dry cell weight of yeast can be observed in both fermentation media when supplemented with nitrogen sources. Based on the result from the experiment, yeast extract was proven to be the best nitrogen sources for ethanol'fermentation due to high amount of ethanol produced (54.73 g/L) compared with peptone (14.27 g/L). Thus, the supplementation of yeast extract is important to achieve fermentation efficiency (99.24%) in fermentation of ethanol using HSS