Optimizing Acid Hydrolysis of Jerusalem Artichoke-Derived Inulin for Fermentative Butanol Production

Abstract

In this study, a central composite design and response surface methodology were used to study the effect of various hydrolysis variables (temperature, pH, and time) on the acid hydrolysis of Jerusalem artichokederived inulin using three different mineral acids (HCl, H 2 SO 4 , and H 3 PO 4 ). Numerical optimization was used to maximize the sugar yield of Jerusalem artichoke powder within the experimental range for each of the mentioned acid. The influence of each acid on the formation of hydroxymethylfurfural (HMF; a known by-product and inhibitor for fermentative organisms) was also investigated. H 2 SO 4 was found to have a better potential for sugar yields compared to two other acids (HCl and H 3 PO 4 ) since it can hydrolyze the highest amount of inulin (98.5 %) under optimal conditions (temperature of 97°C, pH of 2.0, and time period of 35 min) without producing inhibiting HMF concentrations. The sulfuric hydrolysate of Jerusalem artichoke was fermented via solventogenic clostridia to acetonebutanol-ethanol (ABE). An ABE yield of 0.31 g g −1 and an overall fermentation productivity of 0.25 g l −1 h −1 were obtained, indicating the suitability of this feedstock for fermentative ABE production.

Improving Fructose Utilization and Butanol Production by Clostridium acetobutylicum via Extracellular Redox Potential Regulation and Intracellular Metabolite Analysis

“…Jerusalem artichoke (JA) that can grow well in marginal lands is a potential energy crop for biorefinery, and its major biomass is from tubers with inulin as a major carbonhydrate, which can be easily hydrolyzed into a mixture of fructose and glucose at a ratio of %4:1 (w/w). [9,10] JA tubers have been successfully applied for microbial fermentation to produce 2,3-butanediol, lactate, butyrate, and ethanol. [11][12][13][14] However, barriers remain to be addressed for butanol production by C. acetobutylicum from JA tubers due to insufficient fructose utilization, unfavorable acidification, extended lag phase, and poor butanol production and yield.…”

Acid mediated chemical treatment to remove sugar from waste acid stream from nano-crystalline cellulose manufacturing process

“…It has been reported that as compared to HCl, H3PO4, sulfuric acid (H2SO4) had a positive impact on diluted mineral acid catalyzed the hydrolysis of cellulose Sarchami & Rehmann, 2015). Thus, for the current investigation, H2SO4 has considered for dilute mineral acid catalyzed the hydrolysis of the waste sample.…”

Inulin as a Promising Alternative Feedstock for Docosahexaenoic Acid Production by Schizochytrium sp. ATCC 20888

“…[44] Acid hydrolysis is a simple pretreatment to obtain fructose from inulin and the catalyst can be HCl, H 2 SO 4 , or H 3 PO 4 . [45] Microbial inulinases act on the -2,1 bonds of inulin molecules and are categorized into endo-inulinase or exo-inulinase based on the action pattern. [46] The inulin powder was hydrolyzed by sample of fructooligosaccharide (lane 2).…”

“…In previous studies, it was reported that acid hydrolysis of inulin at high temperature resulted in the formation of 5-hydroxymethylfurfural (HMF), a known by-product and inhibitor for some microorganisms. [45,47]…”