Amino acid biosynthetic and antioxidant activity of Brevibacterium sp. InaCC B46 using glucose substrate produced by saccharification of oil palm trunk biomass

Abstract

Brevibacterium sp. is commercially essential due to its production of amino acids, particularly glutamic acid and lysine. This work investigates the effect of Brevibacterium sp. concentration on L-amino acid synthesis from glucose hydrolysed from oil palm trunk biomass as a substrate. The study employed a two-factorial, completely randomised experimental design. Factor A consisted of concentrations of Brevibacterium sp. (1%, 3%, and 5%), while factor B was incubation duration (24 and 48 hours). The study measured the concentrations of four amino acids (alanine, glycine, tyrosine, and glutamic acid) using the colourimetric ninhydrin reaction. Additionally, the viability and antioxidant activity of Brevibacterium sp. during incubation time was measured with spectrophotometry (UV-VIS). The results indicate no significant interaction between factors (P>0.05) but a significant effect (P<0.05) depending on the concentration and incubation time of Brevibacterium sp. InaCCB46 for all parameters. The study found that the biosynthesis of amino acids was most efficient with a 5% concentration of bacteria during 24-hour incubation, resulting in the highest output of alanine, glycine, tyrosine, and glutamic acid at 6.46, 4.58, 6.16, and 6.67 µg/mL, respectively. However, it should be noted that bacterial viability was higher after 24 hours of incubation, ranging from 144.18–216.99% and had strong antioxidant activity at 22.43 ppm.