Agro-wastes and Inert Materials as Supports for the Production of Biosurfactants by Solid-state Fermentation

Abstract: This study explores 9 different biomaterials (agro-wastes) and inert materials, to be used as support in SSF to produce sophorolipids (SLs) with Starmerella bombicola ATCC 22214. Winterization oil filtration cake and sugar beet molasses were the substrates. Biomaterials (lignocellulosic wastes or organic by-products) performed better than inert materials (perlite and polyurethane foams). High yields were obtained for rice husk (0.15 g SLs g⁻¹DM) and wheat straw (0.20 g SLs g⁻¹DM). Lactonic C18:1 predominates over acidic form in the mixture of SLs. The characterization of the process through a time course experiment shows that wheat straw is the best material to produce SLs. A proportional correlation between SLs yield and cumulative oxygen consumption was found, suggesting that cumulative oxygen content (COC) can be used as an indirect measure to monitor the SLs production. Graphic abstract: [Figure not available: see fulltext.].