Screening and kinetics of glutaminase and glutamate decarboxylase producing lactic acid bacteria from fermented Thai foods

Abstract

L-glutaminase and glutamic acid decarboxylase (GAD) catalyzes the hydrolysis of L-glutamine and glutamate, respectively. L-glutaminase widely used in cancer therapy along with a combination of other enzymes and most importantly these enzymes were used in food industries, as a major catalyst of bioconversion. The current investigation was aimed to screen and select L-glutaminase, and GAD producing lactic acid bacteria (LAB). A total of 338 LAB were isolated from fermented meat, fermented fish, fermented soya bean, fermented vegetables and fruits. Among 338 isolates, 22 and 237 LAB has been found to be positive for L-glutaminase and GAD, respectively. We found that 30 days of incubation at 35 ºC and pH 6.0 was the optimum condition for glutaminase activity by G507/1. G254/2 was found to be the best for GAD activity with the optimum condition of pH 6.5, temperature 40 ºC and ten days of incubation. These LAB strains, G507/1 and G254/2, were identified as close relative of Lactobacillus brevis ATCC 14869 and Lactobacillus fermentum NBRC 3956, respectively by 16S rRNA sequencing. Further, improvements in up-stream of the fermentation process with these LAB strains are currently under development.Keywords: L-glutaminase; glutamic acid decarboxylase; lactic acid bacteria and 16S rRNA sequencing.Practical Application: LABs based safe starter culture for the fermentation of mushroom to produce high GABA.

Lactobacillus Paracasei Hii01 Mediated Fermentation of Syzygium Cumini L. Fruits: Assessment of Changes in Phenolic Content and Antioxidant Capacity

“…are commonly used as a starter for the preparation of fermented foods. Food isolate of Lactobacillus brevis, Lactobacillus fermentum was reported to produce glutaminase and glutamate decarboxylase [1] and was used as a starter for two-stage fermentation process of Hericium erinaceus to produce GABA rich mushroom juice [2]. Enterococcus faecalis, protease producing LAB isolated from fermented food, has been used to produce GABA rich H. erinaceus juice [3].…”

Evaluation of factors that influence the L-glutamic and γ-aminobutyric acid production duringHericium erinaceusfermentation by lactic acid bacteria

“…L. brevis HP2 and L. fermentum HP3 strain were used, which were isolated from Thai fermented foods and identified by 16S rRNA sequencing and deposited in the culture collection centre of faculty of Pharmacy, Chiang Mai University, Thailand (Woraharn et al, 2014). These strains were selected for fermentation since they produce significantly higher amounts of glutaminase and GAD (Woraharn et al, 2014). The selected LAB was cultured in MRS broth for seed culture preparation.…”

“…We screened and identified the potential LAB, Lactobacillus brevis HP2 and Lactobacillus fermentum HP3 isolated from Thai fermented foods, which can produce extracellular glutaminase and GAD enzyme, respectively (Woraharn et al, 2014). There have been no comprehensive reports regarding the development of fermented H. erinaceus juice (FHJ) with high amounts of GABA using glutaminase and GAD-producing LAB.…”

Thai Fermented Foods as a Versatile Source of Bioactive Microorganisms—A Comprehensive Review

“…The isolates G507/1 and G254/2 were identified as L. brevis and L. fermentum, respectively. The influence of pH, temperature, and incubation on enzyme activity were studied, and the results suggested that pH values of 6.0 and 6.5, temperatures of 35 and 30 • C, and 10 days of incubation were the optimal condition for L-glutaminase and glutamic acid decarboxylase activity, respectively [44].…”