From fruit waste to enzymes

Abstract

Domestic and municipal solid wastes pose environmental concerns and health risks, suggesting the importance of reduced waste disposal. Food waste accounts for the highest percentage of solid waste in Brunei. An effective strategy is to convert food waste into beneficial products such as enzymes and biofertilizers. This study reports utilization of inedible fruit peels as substrates for enzyme production. A fermentation medium prepared by adding fruit peels, brown sugar and water was allowed to ferment over a period of time. Total carbohydrate content was found to be highest in the fermented orange sample (37.87 ± 4.7 mg/mL) followed by pineapple and banana samples, 11.98 ± 1.45 mg/mL and 10.60 ± 0.45 mg/mL, respectively. Pineapple sample showed the highest concentration of reducing sugar (11.93 mg/mL at week 2 and 3.31 mg/mL after 3 months). Enzyme assay showed that citrus fruits like oranges, yield high activities of enzymes like protease (0.129 U/mL), α-amylase (7.261 ± 0.83 U/mL) and cellulase (0.514 ± 0.03 U/mL). This fermentation product of kitchen waste is economical as it uses cheap raw materials, free of chemical additives and hence eco-friendly.