Open AccessFrom waste to food: Optimising the breakdown of oil palm waste to provide substrate for insects farmed as animal feed
Author(s) -
Elizabeth Dickinson,
Mark D. Harrison,
Marc Parker,
Mike Dickinson,
James Donarski,
Adrian J. Charlton,
Rosie Nolan,
Aida Abouelela Rafat,
Florence J. V. Gschwend,
Jason P. Hallett,
M. Wakefield,
Julie Wilson
Publication year - 2019
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0224771
Subject(s) - digestate , biogas , food waste , pulp and paper industry , biomass (ecology) , elaeis guineensis , bioenergy , waste management , anaerobic digestion , environmental science , substrate (aquarium) , palm kernel , waste treatment , palm oil , food science , microbiology and biotechnology , biofuel , agronomy , chemistry , biology , ecology , organic chemistry , methane , engineering
Waste biomass from the palm oil industry is currently burned as a means of disposal and solutions are required to reduce the environmental impact. Whilst some waste biomass can be recycled to provide green energy such as biogas, this investigation aimed to optimise experimental conditions for recycling palm waste into substrate for insects, farmed as a sustainable high-protein animal feed. NMR spectroscopy and LC-HRMS were used to analyse the composition of palm empty fruit bunches (EFB) under experimental conditions optimised to produce nutritious substrate rather than biogas. Statistical pattern recognition techniques were used to investigate differences in composition for various combinations of pre-processing and anaerobic digestion (AD) methods. Pre-processing methods included steaming, pressure cooking, composting, microwaving, and breaking down the EFB using ionic liquids. AD conditions which were modified in combination with pre-processing methods were ratios of EFB:digestate and pH. Results show that the selection of pre-processing method affects the breakdown of the palm waste and subsequently the substrate composition and biogas production. Although large-scale insect feeding trials will be required to determine nutritional content, we found that conditions can be optimised to recycle palm waste for the production of substrate for insect rearing. Pre-processing EFB using ionic liquid before AD at pH6 with a 2:1 digestate:EFB ratio were found to be the best combination of experimental conditions.