Co-fermentation of cassava waste pulp hydrolysate with molasses to ethanol for economic optimization
Cassava waste pulp (CWP)–enzymatic hydrolysate was co-fermented with molasses (CWP-EH/molasses mixture) with the aim to optimize ethanol production by Saccharomyces cerevisiae TISTR 5606 (SC 90). The optimal fermentation conditions for ethanol production using this mixture were 245 g/L initial total sugar supplemented with KH2PO4 (8 g/L), at 30 °C for 48 h of fermentation under an oxygen-limited condition with agitation at 100 rpm, producing an ethanol concentration of 70.60 g/L (0.31 g ethanol/g total sugar). The addition of cassava tuber fiber (solid residue of CWP after enzymatic hydrolysis) at 30 g/L dry weight to the CWP-EH/molasses mixture increased ethanol production to 74.36 g/L (0.32 g ethanol/g total sugar). Co-fermentation of CWP-EH with molasses had the advantage of not requiring any supplementation of the fermentation mixture with reduced nitrogen.
KeywordsCassava waste pulp Co-fermentation Molasses Ethanol Saccharomyces cerevisiae
The authors thank Dr. Robert Butcher for critical reading of this manuscript and the Thai Alcohol Public Company, Thailand for providing the α-amylase and glucoamylase enzymes. This study was financially supported by the Thai Government budget (fiscal year 2015) and Graduate school, Chulalongkorn University to commemorate the 72nd Birthday Anniversary of His Majesty the King Bhumibol Aduladej.
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