Isolation and identification of L-asparaginase producing bacteria from intestinal bacterial flora of Liza klunzingeri (Day, 1888) and Thunnus tonggol (Bleeker, 1851)

Bacterial L-asparaginase is used as an anti-neoplastic drug for chemotherapy of acute lymphoblastic leukemia and to process cooked or fried foods for prevention of acrylamide formation. Therefore, this enzyme is utilized for controlling and preventing cancer wildly. The aim of the present study was the isolation and identification of potential bacteria producing L-asparaginase from the intestines of Liza klunzingeri and Thunnus tonggol. Accordingly, 44 bacterial strains were initially isolated from those fishes’ intestines using nutrient agar medium. Then, L-asparaginase-producing bacteria were screened using M9 specific solid culture medium, which led to the identification of 20 potential L-asparaginase producing strains. Enzyme production by the isolated bacteria was afterwards evaluated, using as reference enzyme activity. Two strains that displayed the higher enzyme activities, 311 and 284 μmol/min, were selected and identified as Pseudomonas aeruginosa strain HR03 and Pseudomonas stutzeri strain HR04, respectively, by 16S rRNA gene sequence analysis. Overall, the results of this study showed that the intestinal bacterial flora of L. klunzingeri and T. tonggol are promising biological reservoir for the isolation of L-asparaginase producing bacteria. Additionally, marine bacteria P. aeruginosa strain HR03 and P. stutzeri strain HR04 are foreseen as potential bacterial producers of L-asparaginase with application in the pharmaceutical and food industries.