Efficient Simultaneous Saccharification and Fermentation of Inulin to 2,3-Butanediol by Thermophilic Bacillus licheniformis ATCC 14580

Abstract

b 2,3-Butanediol (2,3-BD) is an important starting material for the manufacture of bulk chemicals. For efficient and large-scale production of 2,3-BD through fermentation, low-cost substrates are required. One such substrate, inulin, is a polydisperse fructan found in a wide variety of plants. In this study, a levanase with high inulinase activity and high pH and temperature stability was identified in Bacillus licheniformis strain ATCC 14580. B. licheniformis strain ATCC 14580 was found to efficiently produce 2,3-BD from fructose at 50°C. Then, the levanase was used for simultaneous saccharification and fermentation (SSF) of inulin to 2,3-BD. A fed-batch SSF yielded 103.0 g/liter 2,3-BD in 30 h, with a high productivity of 3.4 g/liter · h. The results suggest that the SSF process developed with the thermophilic B. licheniformis strain used might be a promising alternative for efficient 2,3-BD production from the favorable substrate inulin.

RETRACTED ARTICLE: Engineering Bacillus licheniformis as a thermophilic platform for the production of l-lactic acid from lignocellulose-derived sugars

“…For example, thermophilic bacteria possess highly active cellulolytic and hemicellulolytic enzymes for efficient biomass hydrolysis [8]. Meanwhile, the high-temperature process allows higher rates of feedstock conversion, minimizes the risk of contamination, lowers costs for heating and cooling, permits easier processing of feedstock, and provides opportunities for enhanced product recovery [9].…”

“…For instance, most B. coagulans strains used for l -lactic acid production from lignocellulose-derived sugars exhibited low output [11–14] and were difficult to manipulate genetically [15]. B. licheniformis , a more recently developed thermophilic host, has been successfully used for the production of butane-2,3-diol (2,3-BD) [8, 16, 17], l -lactic acid [18], and d -lactic acid [9]. Unfortunately, the strain utilized cannot effectively use glucose and xylose simultaneously.…”

“…Strain MW3 is a natural producer of 2,3-BD; it can efficiently produce 2,3-BD from glucose at 50–55 °C [8]. With its high cell growth rate, the capability to utilize both hexoses and pentoses, ease of genetic manipulation, and most importantly its GRAS (generally regarded as safe) status, strain MW3 is expected to function as a potential host for biotechnological applications.…”

Carbon Flux Trapping: Highly Efficient Production of Polymer‐Grade d‐Lactic Acid with a Thermophilic d‐Lactate Dehydrogenase

“…The thermotolerant Bacillus licheniformis ATCC 14580 is a facultative anaerobic, Gram‐positive, endospore‐forming bacterium. It is an efficient producer of butane‐2,3‐diol (2,3‐BD), and has a number of potential advantages for fermentation, including: 1) the capability to utilize both hexoses and pentoses, 2) high cell growth rate (shortens fermentation period), 3) ease of genetic manipulation, and 4) GRAS (generally regarded as safe) status by the Food and Drug Administration…”

“…Fermentation conditions are critical for microbial growth and lactic acid secretion . In our previous study, the optimal temperature for cell growth and sugar consumption by strain ATCC 14580 was 50 °C . Thus, we selected this temperature for this study.…”