Bioconversion of Agro-Industrial Waste to Value-Added Product Lycopene by Photosynthetic Bacterium Rhodopseudomonas faecalis and Its Carotenoid Composition

Agro-industrial based industries have produced large amounts of residues. The recycling of agro-industrial wastes to produce value-added products is a promising aspect. The photosynthetic bacterium Rhodopseudomonas faecalis PA2 is an attractive source for carotenoid production because of its high carotenoid productivity. However, carotenoid composition of this bacterium remains unclear. In this study, agro-industrial wastes including soybean meal, coconut meal and cassava meal were optimised as sole substrate to produce carotenoids. Biomass and carotenoid productions were highest in soybean meal medium containing 50% soybean meal. The optimal condition was used to produce this bacterium in a photo-bioreactor and investigate carotenoid composition by using a high performance liquid chromatography (HPLC) and absorption spectral characteristics. The saponified extract consisted of lycopene, 1,2-dihydrolycopene, cis-1,2-dihydrolycopene and 1,2-dihydro-3,4-didehydrolycopene. To our knowledge this is the first study to investigate carotenoid composition of R. faecalis and the bioactive compounds produced by photosynthetic bacteria grown in soybean meal without additional nutrients was proposed. The utilization of this bacterium as a lycopene source with cost competitiveness will be further studied. [GRAPHICS] .