Biodegradation and Nutritional Enrichment of Groundnut Straw by Pleurotus florida

Abstract

The present study was undertaken to evaluate the biochemical transformation and nutritional enhancement of groundnut straw after its utilization as a substrate for the cultivation of Pleurotus florida. The objective was to determine how the fungal biodegradation process during mushroom growth alters the nutritional profile of the substrate, leading to the formation of value-added spent mushroom substrate (SMS). The cultivation of P. florida on groundnut straw resulted in a marked increase in the contents of crude protein (from 3.35% to 5.95%), ash (from 6.75% to 9.30%), and moisture (from 6.90% to 8.45%). Conversely, substantial reductions were observed in pH (from 7.10 to 5.20), crude fiber (from 38.10% to 22.80%), total carbohydrates (from 70.45% to 47.75%), lignin (from 28.45% to 09.30%), cellulose (from 38.25% to 25.85%) and hemicellulose (from 22.45% to 10.75%). These compositional changes reflect the efficient enzymatic degradation of lignocellulosic components by P. florida.
During the vegetative (spawn run) phase, a more rapid breakdown of lignin was observed, indicating intense ligninolytic activity, whereas during the fructification phase, the degradation of lignin slowed and the degradation rates of cellulose and hemicellulose increased, suggesting a metabolic shift to carbohydrate utilization for fruiting body development. The overall findings confirm that bioconversion of groundnut straw by P. florida significantly improves its nutritive quality, particularly by enhancing protein content and reducing fibre fractions. Consequently, the resulting spent mushroom substrate (SMS) becomes more digestible and holds substantial potential as a nutrient-enriched feed resource for ruminants. This study demonstrates an environmentally sustainable strategy for converting agricultural residues into high-value livestock feed while supporting circular bioeconomy concepts.