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Recombinant expression, characterization and application of maltotetraohydrolase from Pseudomonas saccharophila.

BACKGROUND
Maltotetraohydrolase, widely used in food and medical fields, possesses the ability to hydrolyze starch to produce maltooligosaccharides with maltotetraose as the main product. It also has the potential usage in delaying bread aging.


RESULTS
The Pseudomonas saccharophila maltotetraohydrolase was expressed in Bacillus subtilis WS11. SDS-PAGE analysis revealed obvious bands at 57 kDa (maltotetraohydrolase I) and 47 kDa (maltotetraohydrolase II). They showed similar enzymatic properties, but the catalytic efficiency of maltotetraohydrolase I was 4.93 fold higher than that of maltotetraohydrolase II using soluble starch as substrate. In addition, the maltotetraohydrolase production was further scaled up in a 3-L fermentor, and the highest activity reached 1907 U·mL-1 . Then, the recombinant maltotetraohydrolase was used to produce maltotetraose. The maltotetraose yields catalyzed by maltotetraohydrolase I and II reached 73.2% and 69.7%, respectively. Finally, when recombinant maltotetraohydrolase was used in bread-making, texture profile analysis of the bread indicated recombinant maltotetraohydrolase I exhibited significant anti-aging effect.


CONCLUSION
This is the first describing high-efficient expression of P. saccharophila maltotetraohydrolase in the food safety strain B. subtilis, and the yield represented the highest level ever reported. The excellent results were also obtained in preparation of maltotetraose and delaying bread aging using the recombinant maltotetraohydrolase. This study will help lay the foundation for industrial production and application of maltotetraohydrolase. This article is protected by copyright. All rights reserved.