Abstract
Biodiesel has been becoming one of the most promising biofuels for global fuels market in recent years, due to the depletion of global petroleum and its increasing price. Researchers exploit oleaginous microorganisms as an alternative for biodiesel production. Currently, they are focused on reducing the production costs and searching waste materials as substrates. This study aimed to investigate the ability of Serratia marcescens UCP/WFCC 1549 to produce lipids using agro-industrial residues (cassava wastewater and waste vegetable oils), either alone or as additives of Luria Bertani (LB) medium. S. marcescens demonstrated that have good ability for growth in all media employed, mainly in LB medium supplemented with waste vegetable oils. However, the best results for lipids production were obtained in media consisting only by wastes, with values higher than 40% of lipids in biomass. In media comprising only residues, more balanced profiles of fatty acid methyl esters (FAMEs) were found, in terms of the proportion of saturated, mono-unsaturated and poly- unsaturated fatty acids (SFAs, MUFAs and PUFAs, respectively). The best result was obtained in lipids produced in medium containing 6 % cassava wastewater (CW) and 7.5 % waste soybean oil (WSO), which had the highest percentage of MUFAs (48.09 %), in accordance with the standards for biodiesel quality. In addition, a high content of oleic acid (46.82 %) was achieved in this medium, showing S. marcescens UCP/WFCC 1549 as an oleaginous microorganism that can be used as potential feedstock for producing good quality biodiesel. Also, this work demonstrated the suitability of CW and waste vegetable oils for microbial lipids production.
