A thermostable lipase MAS1 from marine Streptomyces
sp. strain was considered as a potential
biocatalyst for industrial application, but its production level was relatively low. Here, the effect of chaperones
co-expression on the secretory expression of lipase MAS1 in Pichia pastoris
Co-expression of protein disulfide isomerase (PDI), HAC1 and immunoglobulin binding protein could
increase the expression level of lipase MAS1, whereas co-expression of
hemoglobin showed a
negative effect to the lipase MAS1 production. Among them, PDI co-expression increased lipase MAS1
expression level by 1.7-fold compared to the control strain harboring only the MAS1 gene. Furthermore,
optimizing production of lipase MAS1 with Pichia pastoris
strain X-33/MAS1-PDI in a 30-L bioreactor were
conducted. Lower induction temperature was found to have a benefit effect for lipase MAS1 production. Lipase
activity at 24 and 22°C showed 1.7 and 2.1-fold to that at 30°C, respectively. Among the induction pH tested,
the highest lipase activity was obtained at pH 6.0 with activity of 440 U/mL after 144 h fermentation.
Our work showed a good example for improving the production of recombinant enzymes in Pichia pastoris
via chaperon co-expression and fermentation condition optimization.