Enzymatic production of an organic soil biostimulant from wheat-condensed distiller solubles: Effects on soil biochemistry and biodiversity

Here, we describe an enzymatic process for soil biostimulant production in which wheat-condensed distiller solubles (WCDS) are converted into a hydrolysate product: WCDS-Enzymatic Extract (WCDS-EE). Physicochemical analyses showed that protein size is the only difference, with WCDS-EE being composed of peptides rather than the original proteins from the raw materials (WCDS). We investigated the influence on soil stimulation and found that dehydrogenase (DHA) and phosphatase (APA) activity, and ATP formation was rapidly increased by both products. However, WCDS-EE was more potent than WCDS. Nevertheless, no differences in bacterial community dynamics were detected using molecular techniques (DGGE of 16S rDNA). We also tested the ability to enhance the biodegradation of petroleum hydrocarbons and found that WCDS-EE is more effective than WCDS. Since the protein size is the most important parameter for biochemical and microbial soil stimulation, this new product could have a high potential for soil recovery, fertilization or bioremediation.