Isolation of lignocellulolytic bacteria from oil palm mesocarp waste

Abstract

In the present investigation, the bacterial strains were isolated from oil palm mesocarp waste dumped soil by serial dilution and pour plate method. The highest lignocellulolytic index was produced by bacterial isolate OPMW 6 (1.5 mm) followed by OPMW 5 (1.2 mm), OPMW 1 (0.83 mm), OPMW3 and OPMW 4 (0.71 mm). Changes in methylene blue color supplemented in nutrient broth from blue to light green or yellow were observed by three bacterial isolates (OPMW1, OPMW 3 and OPMW5), and rest of the bacterial isolatesrecorded less decolourization as the cultures were incubated between 24 and 48 hours respectively with highest percentage of dye decolourization produced by bacterial isolate i.e. OPMW5 (83.3%) and lowest rate ofdecolourization by bacterial isolate OPMW 6 (13.54%) as inoculated in nutrient broth supplemented with methylene blue dye. Utilization of gallic acid as supplemented in minimal salt media recorded positive reactionfor 4 bacterial isolates (OPMW 2, OPMW 5, OPMW 6 and OPMW 8) by the formation of dark colouration and addition ofa-naphthol in MSM inoculated broth culturesshowed formation of purple blue colour due to productionof laccase activity. Among the 4 best isolates having the highest indices, two isolates of bacteria (OPMW5 and OPMW6) had the best lignocellulolytic activity. Based on enzyme biosynthesis ability, the OPMW5 and OPMW6were selected as the best isolates as it can synthesie cellulase and ligninase enzymes. These enzymes are known to accelerate the degradation of oil palm mesocarp fibre substrate.