Bioconversion of agro-industrial by-products into microbial lipids and bioemulsifier by Absidia cylindrospora var. cylindrospora UCP 1301

Abstract

Large amounts of agro-industrial by-products and wastes are generated in Brazil annually. Often, they are underutilized and improperly disposed, causing environmental pollution. In this context, reuse them as raw material to obtain high-added value products, becomes a promising strategy. Hence, this study aimed to investigate the biotechnological potential of the Mucoralean fungus Absidia cylindrospora UCP 1301 for production of oleaginous biomass and bioemulsifier (BE), using agro-industrial by-products as low-cost substrates. Firstly, the morphological identification of the strain was performed for confirmation. Then, fermentations were carried out, according to a 2³ full-factorial design (FFD) in order to evaluate the influence of substrates concentrations on production of biomass, total lipids and BE. The fungus was identified as Absidia cylindrospora var. cylindrospora and the results showed it as an oleaginous microorganism, since it accumulated lipids above 20 % of dry weight. The highest biomass production (11.38 g/L) was found in condition 3 of the FFD, while the highest lipid yield (32.22%) was reached in assay 6. Moreover, this strain was confirmed as a promising BE-producing microorganism, because of it achieved EI24 values above 50% in all conditions of the FFD. The highest EI24 with motor oil (93.3%) was obtained in condition 7 and this emulsion remained stable after 150 days of incubation. Statistical analysis showed that the three agro-industrial by-products had a significant influence on the production of biomass, lipids and BE, confirming the suitability of unconventional substrates for obtaining both microbial oil and emulsifier, which makes this bioprocess attractive for several industries.