Thermal hydrolysate of coconut trunk, coir, and shell as bioherbicide

Abstract

Biomass of coconut trunk, coir, and shell as lignocellulosic waste was partially hydrolyzed in sub-critical temperature for a relatively short time. The process was implemented in an anaerobic condition which produced predominantly phenolics compounds and other complexes’ organic constituents. Base on previous findings, in which allelopathic effects of growing vegetation were sourced by phenolics compounds, the filtrates of the hydrolysates were tested as bioherbicide on Borreria alata as a broadleaf weed. The testing of the weed growth covered the weed response at pre-emergence, early post-emergence, and post-emergence stages. The hydrolysate solution contained phenolic, carboxylic, and ketone groups with a yield of less than 12 mg/kg feedstock after undergoing the thermal hydrolyzation process at subcritical temperature. At the post-emergence stage, coconut shell hydrolysates were capable to suppress the growth of Borreria alata by 13-40% and cause leaf damage at the level of 43-63%. However, its effectivity was higher at the pre-emergence and the early post-emergence stages, where the suppression capacity of shell hydrolysate on the weed growth reached 84-100%.