Effect of initial fermentation medium on bioacetone, biobutanol, and bioethanol (BioABE) production from fermentable sugars of Acacia mangium using Clostridium acetobutylicum YM1

Abstract

Bioacetone, biobutanol, and bioethanol (BioABE) production is dependent on the fermentable sugars produced from lignocellulosic biomass and on the composition and initial pH of the medium. Understanding these process variables and their interconnectedness could enhance the BioABE product yield. Acacia mangium is available abundantly and it is a potential feedstock for BioABE production. In this study, BioABE was produced from fermentable sugars of A. mangium using Clostridium acetobutylicum YM1. Alkaline treated A. mangium (70 °C, 3 h, 5.50 %w/v NaOH) was further hydrolyzed via enzymatic hydrolysis using a multi-enzyme of white rot fungi to convert it into fermentable sugars. Approximately 15 g/L of fermentable sugars was produced from A. mangium (100 g/L) and was used for BioABE production in comparison with glucose. Initial findings showed that only 0.94 g/L of BioABE was produced in comparison with glucose (2.86 g/L) at a pH of 6.2. Decreasing the initial pH of the medium to 4.50 increased the BioABE (2.87 g/L), and after the medium was supplemented with tryptone-yeast-acetate (TYA), the BioABE yield increased by more than 100% to 6.84 g/L. This study discovered that BioABE produced from A. mangium was comparable to using commercial glucose, thus offering high potential as a low-cost feedstock.