SCREENING AND CHARACTERIZATION OF L-GLUTAMINASE PRODUCED BY BACTERIA ISOLATED FROM SANGIHE TALAUD SEA
Abstract: L-glutaminase
(L-glutamine amidohydrolase, EC 3.5.1.2) is a very important enzyme due to its
role as flavor enhancer and antileukemic agent. Salt-tolerant L-glutaminase
produced by marine bacteria is favorable in food industries. This study
describes the screening of L- glutaminase producing marine bacteria from
Sangihe-Talaud Sea, North Sulawesi, Indonesia. Screening of L-glutaminase was
performed using a liquid medium and identification of selected isolate was performed using molecular-based 16S rDNA.
Results showed that there were 7 isolates produced positive results of
L-glutaminase, and one of them (II.1 isolate) produced the highest activity,
i.e 147.99 U/L, equivalent to the specific activity of 62.32 U/mg. The isolate
then selected for further study. Bacterial identification based on 16S rRNA
sequencing has revealed that the isolate was 96% similar to Pseudomonas
aeruginosa strain CG-T8. Characterization of extracellular L-glutaminase from
the II.1 isolate showed that the enzyme worked optimally at temperature of 37-45 °C and pH 7. The enzyme was stable
when NaCl solution was added up to 8% and
began to decrease on addition of NaCl solution of 16% and 20% with
relative activity of 79% and 74%, respectively. The effect of metal ions, e.g
Mn2+, Mg2+, and Co2+ in the form of chloride salt, were able to increase enzyme
activity, whereas the addition of other metal ions (Zn2+, Fe3+, and Ca2+)
decreased the activity. The molecular weights of L-glutaminase was estimated
around 42 kDa and 145 kDa.
Keywords: L-glutaminase,
marine bacteria, 16S rRNA, screening, characterization
Author: Ekowati Chasanah,
Usman Sumo Friend Tambunan, Tanti Yulianti
Journal Code: jpperikanangg120010
