[Construction of recombinant Bacillus subtilis by co-expression of heterologous D-hydantoinase and N-carbamoylase].

Objective: We aimed at co-expressing heterologous D-hydantoinase and N-carbamoylase in Bacillus subtilis, and evaluating the feasibility of producing D-p-hydroxyphenylglycine by the recombinant B. subtilis whole-cell catalysis.

Methods: The Paco expression cassette was combined with the coding sequence of hyd or sd1 gene as an artificial gene to express D-hydantoinase. The PAE expression cassette was combined with the coding sequence of adc gene as an artificial gene to express N-carbamoylase. The D-hydantoinase and N-carbamoylase co-expression plasmids pHCS(sd1+adc) and pHCY(hyd+adc) were constructed, using plasmid pHP13 as carrier; the co-expression plasmids pUCS(sd1+adc) was constructed, using plasmid pUB110 as carrier. The additional copy of acoR and sigL gene was integrated at chromosome. The skf and sdp gene were knocked out in B. subtilis. All recombinant strains bearing co-expression plasmid were characterized by analyzing whole-cell catalysis activity.

Results: In the recombinant strains with plasmid pHCY and with pHCS, the whole-cell catalytic activity reached 0.21 U/mL and 0.31 U/mL, respectively. After the over-expression of acoR, sigL, and high-copy-number pUCS, the whole-cell catalytic activity reached 1.0 U/mL.

Conclusion: Overexpression of acoR, sigL and the deletion of skf, sdp genes had significant effects on the catalysis activity of recombinant whole-cell.