Exploration of low-cost solid waste coffee processing to bio-carotenoids production

Abstract

To solve the high-cost production of natural microbial carotenoids, we sought to use coffee processing of low-cost solid waste, as well as high productivity. In this sense, coffee pulp extract (PE) and coffee husk extract (HE) supplemented were used as substrate to carotenoids production by two yeast strain Rhodotorula mucilaginosa CCMA 0156 and CCMA 0340, and one bacteria strain, Dermacoccus nishinomiyaensis CCMA 0685. Three different solvents were used for the extraction and recovery of intracellular carotenoids. The productivity was evaluated employing Plackett-Burman design and Central Composite Design. Maximum specific carotenoids production (361.29 ± 36.0 µg g-1) was obtained in maximum pulp extract and peptone concentration (6.68% e 10.04 g L-1, respectively) and middle concentration of yeast extract (3 g L-1) by CCMA 0156. Both the pulp and the husk supplemented were suitable substrates to produce carotenoids with maximum production of 361 and 296 μg g-1. The supplementations shall be carried out; however, it is possible replace pure chemical for by-products. After the optimization process, carotenoid production in PE and HE increased 4.43-fold and 3.08-fold, respectively. The best extract process was using acetone: methanol (7:3, v/v). To reduce the cost of carotenoids production the use of solid waste from coffee processing is a good alternative without lose the productivity by yeasts.