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Cui JN, Hu W, Liu YX, Li YL, Hu JH, Liu ZY, Chen JH. Isolation and Screening of High-Yielding α-Amylase Mutants of Bacillus subtilis by Heavy Ion Mutagenesis. Appl Biochem Biotechnol 2023; 195:68-85. [PMID: 35969299 DOI: 10.1007/s12010-022-04097-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/15/2022] [Indexed: 01/13/2023]
Abstract
To improve fermentative production of α-amylase, heavy-ion mutagenesis technology was used to irradiate Bacillus subtilis (B. subtilis) to obtain the high yielding mutants in this study. After continuous cultivation for 12 generations, eight mutants exhibited positive mutation rate with greater H/C. The α-amylase production was stable and obviously exceeded that by the parent strain, which shows that the mutants have a good genetic stability. Among the mutants, the α-amylase activity of B. subtilis KC-180-2 was 72.26 U·mL-1, which was 82.34% higher than that of the original strain. After optimization of fermentation conditions and media, the α-amylase activity of B. subtilis KC-180-2 reached a maximum of 156.83 U·mL-1 at 36 h in a bioreactor. In addition, the optimized fermentation temperature of B. subtilis KC-180-2 was increased to 49℃, indicating B. subtilis KC-180-2 possesses high-temperature resistance, which has great application prospects for industrial fermentation for α-amylase production.
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Affiliation(s)
- Jin-Na Cui
- Center for Energy Conservation and Emission Reduction in Fermentation Industry in Inner Mongolia, Inner Mongolia University of Technology, Hohhot, China.,Engineering Research Center of Inner Mongolia for Green Manufacturing in Bio-Fermentation Industry, Inner Mongolia University of Technology, Hohhot, China.,College of Chemical Engineering, Inner Mongolia University of Technology, Hohhot, China
| | - Wei Hu
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China
| | - Yan-Xin Liu
- Center for Energy Conservation and Emission Reduction in Fermentation Industry in Inner Mongolia, Inner Mongolia University of Technology, Hohhot, China
| | - Yong-Li Li
- Center for Energy Conservation and Emission Reduction in Fermentation Industry in Inner Mongolia, Inner Mongolia University of Technology, Hohhot, China.,Engineering Research Center of Inner Mongolia for Green Manufacturing in Bio-Fermentation Industry, Inner Mongolia University of Technology, Hohhot, China.,College of Chemical Engineering, Inner Mongolia University of Technology, Hohhot, China
| | - Jian-Hua Hu
- Center for Energy Conservation and Emission Reduction in Fermentation Industry in Inner Mongolia, Inner Mongolia University of Technology, Hohhot, China.,Engineering Research Center of Inner Mongolia for Green Manufacturing in Bio-Fermentation Industry, Inner Mongolia University of Technology, Hohhot, China.,College of Chemical Engineering, Inner Mongolia University of Technology, Hohhot, China
| | - Zhan-Ying Liu
- Center for Energy Conservation and Emission Reduction in Fermentation Industry in Inner Mongolia, Inner Mongolia University of Technology, Hohhot, China. .,Engineering Research Center of Inner Mongolia for Green Manufacturing in Bio-Fermentation Industry, Inner Mongolia University of Technology, Hohhot, China. .,College of Chemical Engineering, Inner Mongolia University of Technology, Hohhot, China.
| | - Ji-Hong Chen
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China
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The application of conventional or magnetic materials to support immobilization of amylolytic enzymes for batch and continuous operation of starch hydrolysis processes. REV CHEM ENG 2022. [DOI: 10.1515/revce-2022-0033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Abstract
In the production of ethanol, starches are converted into reducing sugars by liquefaction and saccharification processes, which mainly use soluble amylases. These processes are considered wasteful operations as operations to recover the enzymes are not practical economically so immobilizations of amylases to perform both processes appear to be a promising way to obtain more stable and reusable enzymes, to lower costs of enzymatic conversions, and to reduce enzymes degradation/contamination. Although many reviews on enzyme immobilizations are found, they only discuss immobilizations of α-amylase immobilizations on nanoparticles, but other amylases and support types are not well informed or poorly stated. As the knowledge of the developed supports for most amylase immobilizations being used in starch hydrolysis is important, a review describing about their preparations, characteristics, and applications is herewith presented. Based on the results, two major groups were discovered in the last 20 years, which include conventional and magnetic-based supports. Furthermore, several strategies for preparation and immobilization processes, which are more advanced than the previous generation, were also revealed. Although most of the starch hydrolysis processes were conducted in batches, opportunities to develop continuous reactors are offered. However, the continuous operations are difficult to be employed by magnetic-based amylases.
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