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Hyaluronic acid production by recombinant Streptococcus thermophilus

Paper ID Volume ID Publish Year Pages File Format Full-Text
21615 43231 2011 6 PDF Available
Title
Hyaluronic acid production by recombinant Streptococcus thermophilus
Abstract

ABSTRACTGenerally recognized as safe, Streptococcus thermophilus was transformed using a plasmid expressing endogenous hyaluronic acid (HA) synthase genes. A single expression of hyaluronic acid synthase (hasA), uridine diphosphate-glucose dehydrogenase gene (hasB), or pyrophosphorylase gene (glmU) and double expression of hasA and hasB were attempted. A streptococcus–Escherichia coli shuttle vector, pBE31, was successfully transfected in S. thermophilus. The single expression of hasA or hasB allowed S. thermophilus to produce about 0.5–1.0 g/l HA. The strains coexpressing of hasA and hasB showed a markedly increased HA production (1.2 g/l) which was six-fold increase compared with the wild-type strain. The maximum cell concentration and specific growth rate of each recombinant strain were lower than those of the wild-type strain; however, the specific production rate was more than 100-fold higher. Galactose concentration decreased in the coexpressing strain after depletion of lactose. The bacterial metabolism would be altered in order to achieve a higher production by changing the intracellular metabolism. The average molecular weight of HA (1.0 × 106 Da) was not affected by the expression of hasA and hasB. HA produced from recombinant strain could be an alternative material for medical, cosmetic and food utilization instead of HA from conventional pathogenic streptococci.

Keywords
Hyaluronic acid; Streptococcus thermophilus; pBE31; Hyaluronic acid synthase; Leloir pathway
First Page Preview
Hyaluronic acid production by recombinant Streptococcus thermophilus
Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Bioscience and Bioengineering - Volume 111, Issue 6, June 2011, Pages 665–670
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering