Identification of Corn Chaff as An Optimal Substrate for the Production of Rhamnolipids in Pseudomonas aeruginosa Fermentations

Waste biomass deriving from agricultural activities has different destinations depending on the possibility to apply it to specific processes. As the waste biomass is abundant, cheap and generally safe, it can be used for several applications, being biogas production the most relevant from the quantitative point of view. In this study, we have used as substrates for the microbial production, a set of agricultural by-products deriving from the post-harvest treatment of cereals and legumes. Some of the by-products used in the study, and tested without any pre-treatment, were easily metabolized and were highly effective for the growth of microorganisms. Besides allowing growth of the microorganisms, the formulation of the waste agricultural biomass with a reduced set of nutrients routinely used in fermentation, stimulated biosurfactants productions in the range of tenths of grams of the pure products. In particular, the use of mechanically treated corn chaff (“bees wings”) was suitable for the production of rhamnolipids. This study demonstrated that the use of alternative raw materials could be applied to reduce the carbon footprint of industrial productions without compromising the possibility of having suitable processes for the industrial production of high added value molecules.