L-asparaginase production in the pseudomonas pseudoalcaligenes strain JHS-71 isolated from Jooshan Hot-spring

Abstract

L-asparaginase has lots of medical and industrial applications. Ever since L-asparaginase anti-tumor activity was first demonstrated, its production using microbial systems has attracted considerable attention owing to their cost-effective and eco-friendly nature. The aim of this study is to obtain L-asparaginase producing bacteria and determining the enzyme activity. Samples were picked up from Jooshan hot springs located in the Sirch, Kerman. The L-asparaginase producing bacteria were screened on the agar medium supplied with L-asparagine and phenol red indicator dye (pH-7.0). L-asparaginase activity was detected on the basis of pink color around the colony. Enzyme production was also performed based on ammonia detection by Nessler method. Among 24 strains, there were 7 strains which could produce L-asparaginase.Sequencing of 16S rRNA showed that, the best isolates producing L-asparaginase belongs to the Pseudomonas genus. Enzyme activity after 24 and 48 h of incubation showed that Pseudomonas pseudoalcaligenes strain JHS-71was the best strain that produced L-Asparaginase about 240 (U/ml) after 48h of incubation. Results showed that, L-Asparaginase activity enhanced about 27% in the presence of Co+2. L-asparaginase JHS-71 retained more than 50% of its initial activity in the presence of Cu+2, Mn+2, Zn+2, Mg+2 and Fe+2. Because of various applications of L-asparaginase in biotechnology, P. pseudoalcaligenes strain JHS-71 can be used as a suitable candidate in these fields.