The invention discloses a method for improving the yield of Bacillus subtilis acetylglucosamine, which belongs to the technical field of genetic engineering. In the invention, the recombinant Bacillus subtilis S5 (S5-PxylA-glmS-P43-GNA1) is taken as a starting strain, and the glmS ribozyme is integrated into the mid of rbs and the promoter sequence of the glmM and pfkA gene, respectively. The ribozyme mutant has the advantage of prolonging the stability of the mRNA and integrated into the mid of rbs and the promoter sequence of the pgi gene. The yield of GlcNAc of the recombinant strain reaches 11.79-20.05 g/L. This laid the foundation for the further metabolic engineering of Bacillus subtilis to produce GlcNAc.

The present invention relates to the field of biotechnology engineering. It provides a recombinant Escherichia coli that can produce fructosylated chondroitin with high yields and the method for constructing the recombinant strain. The present invention discloses a method for constructing an expression plasmid pETM6R1-RBS-glmM-GGGS-glmS that contains a glmM and a glmS gene under regulation of ribosome binding sites. The recombinant plasmid was transformed into E. coli K4 to obtain a recombinant E. coli strain ZQ33 that can produce fructosylated chondroitin up to 3.99 g.Math.L.sup.1 by fed-batch fermentation in a 5-L fermentor, which was increased by 108.90% compared to that of the wild type strain.

The present invention relates to the field of biotechnology engineering. It provides a method of constructing a recombinant Bacillus subtilis that can produce specific-molecular-weight hyaluronic acids. By integranted expression of hasA from Streptococcus zooepidemicus and overexpression of genes of HA synthetic pathway, tuaD, glmU and glmS, high yield HA production was achieved in the recombinant strain. Additionally, introduction and functional expression of the leech hyaluronidase in the recombinant strain substantially increased the yield of HA to 19.38 g.Math.L.sup.1. Moreover, HAs with a broad range of molecular weights (10.sup.3 Da to 10.sup.6 MDa) were efficiently produced by controlling the expression level of hyaluronidase using RBS mutants with different translational strengths. The method of the present invention can be used to produce low molecular weight HAs at large scale in industrial applications.

The present invention relates to the field of biotechnology engineering. It provides a method of constructing a recombinant Bacillus subtilis that can produce specific-molecular-weight hyaluronic acids. By integranted expression of hasA from Streptococcus zooepidemicus and overexpression of genes of HA synthetic pathway, tuaD, glmU and glmS, high yield HA production was achieved in the recombinant strain. Additionally, introduction and functional expression of the leech hyaluronidase in the recombinant strain substantially increased the yield of HA to 19.38 g.Math.L.sup.1. Moreover, HAs with a broad range of molecular weights (10.sup.3 Da to 10.sup.6 MDa) were efficiently produced by controlling the expression level of hyaluronidase using RBS mutants with different translational strengths. The method of the present invention can be used to produce low molecular weight HAs at large scale in industrial applications.

The present invention relates to a method for producing lacto-N-tetraose (LNT) and lacto-N-neotetraose (LNnT) using Corynebacterium glutamicum, and more specifically to: recombinant Corynebacterium glutamicum transformed such that, in order to increase productivity of LNT and LNnT, genes introduced from outside are expressed in Corynebacterium glutamicum, and genes inherent in Corynebacterium glutamicum are overexpressed; and a method for producing LNT and LNnT using same. Accordingly, the present invention uses Corynebacterium glutamicum so as to enable producing LNT and LNnT in a safe manner and in high concentration, high yield, high productivity, compared to when using conventional Escherichia coli.