Ethanol productivity optimization by molasses-cassava waste pulp mixture fermentation

Abstract

Molasses was co-fermented with cassava waste pulp (CWP) hydrolysate to ethanol by Saccharomyces cerevisiae TISTR 5606 (SC 90) for economic optimization. The optimal condition found for ethanol production from the mixture of molasses and CWP-enzymatic hydrolysate (molasses/CWP-EH) was 245 g/l initial total sugar supplemented with 8g/l KH2PO4 when fermented for 48 h at 30 °C under an oxygen limited condition with agitation at 100 rpm, to give an ethanol of 70.60 g/L (0.31 g ethanol/g total sugar). The molasses/CWP-EH containing cassava tuber fiber (CTF, solid residue of CWP after enzymatic hydrolysis) at 30 g/l dry weight increased the ethanol production to 74.36 g/L (0.32 g ethanol/g total sugar). Co-fermentation of molasses with CWP-EH had the advantage of not requiring any supplementation of the ferment with reduced nitrogen.