Effective continuous acetone–butanol–ethanol production with full utilization of cassava by immobilized symbiotic TSH06

Abstract

Background Butanol production by fermentation has recently attracted increasingly more attention because of its mild reaction conditions and environmentally friendly properties. However, traditional feedstocks, such as corn, are food supplies for human beings and are expensive and not suitable for butanol production at a large scale. In this study, acetone, butanol, and ethanol (ABE) fermentation with non-pretreated cassava using a symbiotic TSH06 was investigated. Results In batch fermentation, the butanol concentration of 11.6 g/L was obtained with a productivity of 0.16 g/L/h, which was similar to that obtained from glucose system. A full utilization system of cassava was constructed to improve the fermentation performance, cassava flour was used as the substrate and cassava peel residue was used as the immobilization carrier. ABE fermentation with immobilized cells resulted in total ABE and butanol concentrations of 20 g/L and 13.3 g/L, which were 13.6% and 14.7% higher, respectively, than those of free cells. To further improve the solvent productivity, continuous fermentation was conducted with immobilized cells. In single-stage continuous fermentation, the concentrations of total ABE and butanol reached 9.3 g/L and 6.3 g/L with ABE and butanol productivities of 1.86 g/L/h and 1.26 g/L/h, respectively. In addition, both of the high product concentration and high solvent productivity were achieved in a three-stage continuous fermentation. The ABE productivity and concentration was 1.12 g/L/h and 16.8 g/L, respectively. Conclusions The results indicate that TSH06 could produce solvents from cassava effectively. This study shows that ABE fermentation with cassava as a substrate could be an efficient and economical method of butanol production.

Continuous Fermentation Coupled with Online Gas Stripping for Effective Biobutanol Production

“…In the previous study, it was found that TSH06 has the ability to directly produce butanol from cassava flour, without the pretreatment enzymatic hydrolysis or gelatinization [8]. Considering that the concentration of substrate can affect the fermentation performance, in this work, different concentrations of cassava media were used for butanol fermentation to observe the butanol synthesis by TSH06.…”

“…In the previous study, it was found that continuous fermentation reached a steady state within 24-36 h of initiation. Therefore, the gas-stripping device was activated after 36 h of continuous fermentation [8]. After 36 h of continuous fermentation, the concentration of butanol was 8.8 g/L.…”

“…Cassava can grow in poor soil and does not compete for land with other starch crops such as corn and wheat [7]. At the same time, in China and Southeast Asian countries, cassava is primarily cultivated as a non-food crop, mainly for starch production and feed processing [8]. Therefore, cassava is a promising material for butanol fermentation that can replace corn.…”

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

“…On the other hand, use of butanol as a biofuel has remarkable advantages over ethanol in terms of higher energy, low volatility and can be mixed or completely replace current fuel systems (Green, 2011). Cassava flour, gelatinized starch and starch hydrolysate have been fermented to produce butanol (Lin et al, 2019; T. Li et al, 2015; Thang et al, 2010). The fermentation of cassava starch hydrolysate produced the highest butanol concentration of 25.7 g/L (Lépiz‐Aguilar et al, 2013).…”

Application of fed-batch strategy to fully eliminate the negative effect of lignocellulose-derived inhibitors in ABE fermentation

“…This leads to a partial loss of soluble carbohydrates from hemicelluloses, an increase in required process steps and increased water and chemical consumption. Another promising approach is to search for or construct more tolerant strains [ 33 – 35 ]; the use of multispecies consortia [ 36 ] and strains having inherent enhanced detoxification capacity [ 14 ].…”