Screening, identification and growth characteristics of a low-temperature proteinase producing strain

Through the plate separation and the proteinase activity determination, nine low- temperature proteinase producing strains were obtained from the permafrost in the region of Altai, Xinjiang, in which the strain A29-2 had the highest proteinase activity, reaching to 31.88U /mL.The growth of A29-2 reached the maximum level under the condition of initial pH7.0, mass fraction of NaCl 1.00%, temperature 22℃.Based on the morphological observation, physiological and biochemical identification and 16S rDNA sequence analysis, the strain A29- 2 was identified as Serratia sp..The activity of proteinase produced by A29-2 remained mostly unchanged after 48h of stored at 4℃.The results indicated that proteinase produced by cold-adapted strains was low-temperature enzyme.