Effect of temperature on acid hydrolysis of Jerusalem artichoke as raw material for ethanol production

Abstract

Jerusalem artichoke (JA) is a low-requirement crop, which does not interfere with food chain, and is a promising carbon source for industrial fermentation. Microbial conversion of such a renewable raw material to useful products, such as ethanol, is an important objective in industrial biotechnology. In this study, ethanol was efficiently produced from the hydrolyzates of JA obtained at different pH values (pH 2.5, pH 3.0 and pH 3.5), temperature (120, 130, 132 and 134?C) and hold time (30 and 60 min) by Saccharomyces cerevisiae. The efficient degradation of JA by HCl under certain experimental conditions was confirmed by thin-layer chromatography. Ethanol concentration of 7.52% (w/w), which corresponds to 93.89 % of the theoretical yield is achieved by ethanol fermentation of JA hydrolyzate obtained at pH 2.5. [Projekat Ministarstva nauke Republike Srbije, br. TR-31002]

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

“…Samples for analysis were randomly taken from the available material and the small standard deviation indicates the compositional homogeneity of the tubers. The measured values are in agreement with values typically found for Jerusalem artichoke [12][13][14][15][16][17][18][19][20][21][22][23][24].…”

“…c pH and time using H 3 PO 4 as catalyst artichoke tubers using different mineral acids and to compare the effectiveness of each acid on hydrolysis at optimal conditions. In a closely related study, the hydrolysis of Jerusalem artichoke tubers was carried out using HCl at a temperature of 120°C, pH of 2.5, for 60 min resulting in 68 % hydrolysis of inulin [17], which is lower than the results obtained in this study. It has been reported that the sugar yield, evaluated as fructose and glucose production, is very heat sensitive in acidic conditions as the products easily degrade at temperature higher than 97°C [19], as was the case for the work of Razmovski et al [20], resulting in a lower hydrolysis yield.…”

“…An increase in temperature, decrease in the pH, and increase in hydrolysis time are expected to result in an increase of HMF during dilute acid hydrolysis [17][18][19][20] which is also the result of this study. However, the use of less-intense conditions, temperature of 80 to 97°C, and time of 7 to 40 min resulted in a low amount of HMF (0.0-6.4 mg HMF g −1 reducing sugar ).…”

“…Among mineral acids, hydrochloric acid, sulphuric acid, and phosphoric acid have been used in many studies for inulin hydrolysis; however, the available literature provides little information about the optimum condition and yield of inulin hydrolysis, nor a controlled comparison of different acids [13,[17][18][19][20]. Also the information about potentially fermentation-inhibiting hydrolysis by-product (HMF) is limited in the current literature.…”