Integral use of rice husks for bioconversion with white-rot fungi

Rice cultivation is an important agroindustry in Colombia that produces large quantities of lignocellulosic biomass during the post-harvest stage. When this residual biomass accumulates, it causes environmental problems. One alternative solution to this question is the transformation of waste by way of white-rot fungi, which can generate a variety of bio-transformed products. The present study evaluated different biotechnological alternatives for the utilization and transformation of rice crop by-products through the use of white-rot fungi. Laccase and endoglucanase activity, analysis proximal, preliminary identification of terpenes, and quantification of polysaccharides total and beta-glucans were performed with spent substrate and mushrooms of Pycnoporus sanguineus and Pleurotus tubarius obtained by way of solid-state fermentation. The three strains of fungi evaluated demonstrated a relationship between proximal substrate composition and mycelial growth. Proximal analysis of mushrooms and spent mushrooms substrate showed protein content between 2.94 and 16.32 and fiber percentages of 25.72%, as well as phosphorous, sulfur, calcium, magnesium, potassium, iron, and sodium content. Mushrooms of P.tubarius showed greater polysaccharide and beta-glucan content, and in all obtained products, steroids and saturated triterpenes were found. Rice husks are good inductors for the laccase activity of P. sanguineus and L. crinitus, as well as for the endoglucanase activity of P. sanguineus and P. tubarius. This investigation demonstrated that wild fungus strains may transform rice husks into products with added value, whether as food sources or for use in different sectors of the industry.

Automated summary

This study evaluated different biotechnological alternatives for the utilization and transformation of rice crop by-products through the use of white-rot fungi. The results showed that wild fungus strains can transform rice husks into products with added value and a variety of bio-transformed products were identified. This is of great importance for addressing the environmental problems caused by the accumulation of rice crop by-products and developing new resources.