Isolation, molecular identification and production investigation of Bacillus-producing L-Asparaginase from Jiroft microflora

Cancer cells are not capable of producing L-asparagine, and mainly are depended to the L-asparagine from the circulating plasma pools. L-Asparaginase (L-asparagine amidohydrolase EC 3.5.1.1) catalysis the conversion of L-asparagine to L-aspartate and ammonium. L-asparaginase is the first enzyme with anti-leukemic activity to be intensively studied in human beings. Isolation and identification of L-asparaginase producing bacteria from Jiroft microflora was the aim of this study.
In this sectional study, soil and water samples were collected from citrus orchards and waste of milk factory in Jiroft, Kerman province. The bacterial-producing L-asparaginase was screened on agar medium supplied with L-asparagine and phenol red indicator dye. L-asparaginase activity was detected on the basis of pink color around the colony. The best strains were finally identified using PCR method.
16S rRNA sequencing results showed that the best isolate-producing L-asparaginase belonged to the Bacillus genus. DJK23 strain produced the maximum L-asparaginase, approximately 165 U/ml. The our analysis showed that L-asparaginase was active in a pH rang of 5 to 8, with maximal enzyme activity at pH 7. It is mentioned that this enzyme retains 36% of its initial activity at pH 5.
Although L-asparaginase from bacteria has been extensively characterized, a similar attention has not been paid to Bacillus. These results showed that Bacillus L-Asparaginase has desirable activity in the presence of neutral and acidic pH, which can be considered as a therapeutic and industrial enzyme.