Green and sustainable biocatalytic production of 3,4,5-trihydroxycinnamic acid from palm oil mill effluent

Palm oil mill effluent (POME) is a major waste product of the palm oil industry. This work describes the development and utilization of an effective protocol to analyze and extract phenolic acids from POME. p-Coumaric acid (CMA) and caffeic acid (CFA) were identified as major constituents. We therefore developed a protocol to synthesize 3,4,5-trihydroxycinnamic acid (3,4,5-THCA), a strong antioxidant with potential use as a medicinal agent, based on the biocatalytic reaction of p-hydroxyphenylacetate hydroxylase (HPAH) with CMA as a substrate. The reaction showed greater efficiency than previous protocols in terms of cost (1/10 reduction), scale (40-50 fold increase) and production time (1/3 reduction). The protocol could be used successfully in the bioconversion of CMA and CFA extracted from POME to generate 3,4,5-THCA. This is the first report to demonstrate the production of 3,4,5-THCA from a renewable and sustainable biomass feedstock using a method that abides by all of the principles of green chemistry, paving the road for future development so that palm oil industries and farmers can receive high economic benefit.