Liquid hot water extraction as a chemical-free pretreatment approach for biobutanol production from Cassia fistula pods

Abstract

© 2020 Elsevier Ltd The present investigation was carried with accessible roadside ornamental tree waste, Cassia fistula pods (CFP) for biobutanol production using Clostridium acetobutylicum TISTR 2375 through various methodologies compositional analysis, extraction, saccharification, and fermentation. The results of the liquid hot water extraction (LHW) in CFP revealed that the optimal condition at temperature 63 °C for 40 min and 96 °C for 60 min. The sugar concentration at the optimal condition has 258.82 g/L total sugar and 57.22 g/L, reducing sugar, respectively. CFP materials that have been LHW extracted and processed hydrolysis with cellulase enzymes. It was found that the total sugar concentration was increased from 272.34 ± 5.65 g/L to 344.48 ± 19.74 g/L; also the reducing sugar concentration was increased from 55.24 ± 4.36 g/L to 144.29 ± 30.74 g/L. At the early stage, high sugar concentrations cause inhibition of the development of the cells, which limits the fermentation. This study finding suggested that sugar dilution is an essential step for efficient butanol production by a strain of C. acetobutylicum TISTR 2375.