Authors : Rachma Wikandari, Ria Millati, Siti Syamsiyah, Ririn Muriana and Yuliana Ayuningsih
Abstract: Yeast isolate of Bekonang has been being applied for many years in ethanol home industry of Bekonang, Central Java, Indonesia. Its tolerance against furfural, Hydroxymethylfurfural (HMF) and acetic acid as the most by product components in acid hydrolysate was investigated. Isolate of Bekonang was cultivated on 50 g glucose L-1 at 30°C for 48 h under aerobic condition. Each flask was added with different concentrations of furfural (0.25, 0.5, 1, 1.5 g L-1), HMF (0.5, 1, 2, 3 g L-1) and acetic acid (0.75, 1.5, 3, 4.5, 6 g L-1). During fermentation, glucose consumption, ethanol yield and productivity were examined and compared with a reference. The results show that was completely consumed in the media with addition of furfural and HMF up to 0.5 g L-1 as well as in the presence of acetic acid up to 6 g L-1. Addition of 0.5 g L-1 of furfural and HMF only decreased both ethanol yield and productivity for <10%. However in the presence of furfural and HMF at 1 g L-1, the ethanol yields were decreased by 26 and 18.45%, respectively and ethanol productivities were decreased by 73 and 71%, respectively. Additions of acetic acid up to 1.5 g L-1 result in increasing both ethanol yield and productivity up to 6.96 and 6.89%, respectively. However, higher concentrations of acetic acid up to 1.5 g L-1 caused decreased ethanol yield and productivity. Addition of acetic acid in all tested concentrations results in acceptable range of ethanol yield and productivity compared with the reference. These findings show that furfural and HMF were inhibitors to the Isolate of Bekonang, while acetic acid can behave as a friend or foe depending on its concentration.
Rachma Wikandari, Ria Millati, Siti Syamsiyah, Ririn Muriana and Yuliana Ayuningsih, 2010. Effect of Furfural, Hydroxymethylfurfural and Acetic Acid on Indigeneous Microbial Isolate for Bioethanol Production. Agricultural Journal, 5: 105-109.