Enhanced isopropanol and n-butanol production by supplying exogenous acetic acid via co-culturing two clostridium strains from cassava bagasse hydrolysate

Abstract

The focus of this study was to produce isopropanol and butanol (IB) from dilute sulfuric acid treated cassava bagasse hydrolysate (SACBH), and improve IB production by co-culturing Clostridium beijerinckii (C. beijerinckii) with Clostridium tyrobutyricum (C. tyrobutyricum) in an immobilized-cell fermentation system. Concentrated SACBH could be converted to solvents efficiently by immobilized pure culture of C. beijerinckii. Considerable solvent concentrations of 6.19 g/L isopropanol and 12.32 g/L butanol were obtained from batch fermentation, and the total solvent yield and volumetric productivity were 0.42 g/g and 0.30 g/L/h, respectively. Furthermore, the concentrations of isopropanol and butanol increased to 7.63 and 13.26 g/L, respectively, under the immobilized co-culture conditions when concentrated SACBH was used as the carbon source. The concentrations of isopropanol and butanol from the immobilized co-culture fermentation were, respectively, 42.62 and 25.45 % higher than the production resulting from pure culture fermentation. The total solvent yield and volumetric productivity increased to 0.51 g/g and 0.44 g/L/h when co-culture conditions were utilized. Our results indicated that SACBH could be used as an economically favorable carbon source or substrate for IB production using immobilized fermentation. Additionally, IB production could be significantly improved by co-culture immobilization, which provides extracellular acetic acid to C. beijerinckii from C. tyrobutyricum. This study provided a technically feasible and cost-efficient way for IB production using cassava bagasse, which may be suitable for industrial solvent production.

Cassava (Manihot esculenta) dual use for food and bioenergy: A review

“…After root tuber harvest, the non-food parts of cassava, including stem, leaves and by-products, such as cassava peel, bagasse or pulp generated from starch separation normally go to waste. These contain higher amounts of Elimination of toxic cyanogen glycosides Gomez et al (2021) lignocellulose that can be efficiently converted into biofuels (Lu et al, 2012;Zhang et al, 2016). The cassava stem comprises 15% of starch, cellulose (30-50%) and hemicellulose (20-30%) (Han et al, 2011;Sovorawet & Kongkiattikajorn, 2012).…”

Advances and Applications of Clostridium Co-culture Systems in Biotechnology

“…Luo et al achieved high total ABE concentrations of 24.8 g/L including 16.3 g/L of butanol via the added butyrate fermentative supernatant produced by C. tyrobutyricum, which can produce butyric acid from fermentable sugars in the C. acetobutylicum ATCC824 and Saccharomyces cerevisiae co-culture (Luo et al, 2017). Moreover, C. tyrobutyricum was also co-cultured with C. beijerinckii ATCC6014 to increase butanol production (Zhang et al, 2016a). Recently, Ebrahimi et al (2019) found the coculture of C. acetobutylicum and Nesterenkonia sp.…”

Development of Clostridium tyrobutyricum as a Microbial Cell Factory for the Production of Fuel and Chemical Intermediates From Lignocellulosic Feedstocks

“…Co-fermentations with other bacteria have also been leveraged to capitalize on different metabolic machinery without cloning. Using C. tyrobutyricum to supply C beijerinckii with organic acids for re-uptake has had success with several different hydrolysates, yielding target biochemicals like n-butanol, isopropanol, and butyl-butyrate ( Table 1; Li et al, 2013;Zhang et al, 2016;Cui et al, 2020). Additionally, C tyrobutyricum has benefited from the levansucrase enzyme in the Bacillus SGP1 strain, which has the capacity to hydrolyze sucrose and provides convertible monomers for C tyrobutyricum to upgrade into butyric acid ( Table 1; Dwidar et al, 2013).…”