Effects and statistical optimization of fermentation conditions on growth and poly (vinyl alcohol)-degrading enzyme production of Streptomyces venezuelae GY1

The effects of environmental conditions, including temperature, pH and dissolved oxygen, on growth and production of polyvinyl alcohol (PVA)-degrading enzymes of the newly-isolated strain Streptomyces venezuelae GY1 were investigated. The medium composition for strain GY1 was studied first by single factorial design and then optimized using a central composite design. PVA with high saponification is better for growth of, and PVA-degrading enzyme production by S. venezuelae GY1 compared with PVA with low saponification, in contrast with the characteristics of other bacteria producing PVA-degrading enzymes. The optimal temperature and initial pH for production of PVA-degrading enzyme by strain GY1 was 30 degrees C and 7.0, respectively. The optimal medium composition for PVA-degrading enzyme production is: 1.01 g L(-1) of PVA1799, 0.307 g L(-1) of NaNO(3) and 0.512 g L(-1) of MgSO(4)center dot 7H(2)O.