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Copyright of Journal of Food Science & Biotechnology is the property of Journal of Food Science & Biotechnology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Dalian Polytechnic University is the property of Journal of Dalian Polytechnic University Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Modern Food Science & Technology is the property of Editorial Office of Modern Food Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Dalian Polytechnic University is the property of Journal of Dalian Polytechnic University Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of China Brewing is the property of China Brewing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Dalian Polytechnic University is the property of Journal of Dalian Polytechnic University Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

L-arabinose isomerase (L-AI) is the key enzyme that isomerizes D-galactose to D-tagatose. In this study, to improve the activity of L-arabinose isomerase on D-galactose and its conversion rate in biotransformation, an L-arabinose isomerase from Lactobacillus fermentum CGMCC2921 was recombinantly expressed and applied in biotransformation. Moreover, its substrate binding pocket was rationally designed to improve the affinity and catalytic activity on D-galactose. We show that the conversion of D-galactose by variant F279I was increased 1.4 times that of the wild-type enzyme. The K m and k cat values of the double mutant M185A/F279I obtained by superimposed mutation were 530.8 mmol/L and 19.9 s -1 , respectively, and the catalytic efficiency was increased 8.2 times that of the wild type. When 400 g/L lactose was used as the substrate, the conversion rate of M185A/F279I reached a high level of 22.8%, which shows great application potential for the enzymatic production of tagatose from lactose.

L-arabinose isomerase catalyzes the isomerization reaction from D-galactose to D-tagatose, and has attracted more attention due to its importance in animal nutrition and food applied research. Animal rumen is a special anaerobic environment, and ruminal microorganisms contain large amounts of novel genes that code for polysaccharide-degrading enzymes. This stud)' primarily analyzed the genetic diversity of L-arabinose isomerase in sheep rumen bacteria. Using the metagenome of rumen content extracted 4 h after feeding as template, 61 L-arabinose isomerase gene fragments with 68%~98% identities and known sequences were obtained by PCR amplification with specific degenerate primers and restriction enzyme digest. Of them, 38 distinct sequences (<95% identity) were subjected to clustering analysis. The results showed that the L-arabinose isomerase genes from Prevotella ruminicola were found to be predominant (36/38) in sheep rumen, and those from Catonella morbid and Marinilabilia salmonicolor (2/38) were minor. This study has not only enriched the genetic resources of L-arabinose isomerase, but also determined the importance of Prevotella in sheep rumen. [ABSTRACT FROM AUTHOR]