Combined effect of olive pruning residues and spent coffee grounds on Pleurotus ostreatus production, composition, and nutritional value

Abstract

No previous study assessed the combined effect of olive pruning residues (OLPR) and spent coffee grounds (SCG) on P. ostreatus production and nutritional value. The aim of this study was to determine the capacity of P. ostreatus to degrade lignocellulosic nature of combined OLPR and SCG as well as their resultant nutrient composition. A complete randomized design was adopted with five treatments: S1:100%wheat straw (WS) (control), S2:33%WS+33%SCG+33%OLPR,S3:66%WS+17%SCG+17%OLPR,S4:17%WS+66%SCG+17%OLPR, and S5:17%WS+17%SCG+66%OLPR, and ten replicates per treatment. Substrate’s and mushroom’s composition were analyzed on chemical scale, including fatty acids and heavy metals profiles, following international standards. Only S1, S2, and S3 were productive, with comparable biological yield, economical yield, and biological efficiency. Organic matter loss decreased with increasing proportions of OLPR and SCG. Percentage lignin loss was higher in S1 than in S2 and S3 (53.51, 26.25, and 46.15% respectively). Mushrooms of S3 had some enhanced nutritional attributes compared to control: decrease in fat, increase in protein, increase in monounsaturated fatty acids, and lower zinc accumulation. Lead was less accumulated in S2 than S1 mushrooms. Sodium content of mushroom decreased in S2 and S3. The latter substrates yielded mushrooms with lower polyunsaturated fatty acids (PUFA) and higher saturated fatty acids (SFA) contents. All mushrooms had a valuable PUFA/SFA. This study suggests using OLPR and SCG in low proportions as nutritional supplements to the commercial wheat straw.

Risk Assessment of Heavy Metals Occurrence in Two Wild Edible Oyster Mushrooms (Pleurotus spp.) Collected from Rajaji National Park

“…Recently, it was acknowledged that P. ostreatus grown on agro-industrial residues such as olive pruning residues and spent coffee grounds had the potential to accumulate some desirable and undesirable metals. However, the reported concentrations were within the same limits set by the European Commission (EC), World Health Organization (WHO), and United States Food and Drug Administration (FDA) [ 15 ]. In the same vein, P. ostreatus , grown on spent mushroom substrate, supplemented with nano-amino additives outlined high Pb levels, (>0.3 mg/kg) exceeding limits set by the guidelines, which stipulate the need to reconsider consuming the produce regularly [ 14 ].…”

Producción del Pleurotus ostreatus utilizando cáscaras de maíz y leguminosas

“…Los residuos agrícolas, agroindustriales y urbanos, de origen vegetal, presentan un alto contenido de celulosa; un polímero de glucosa; que es el principal componente de la pared celular de las plantas (Díaz Muñoz et al, 2019). Pleurotus ostreatus es un saprofito, con alta flexibilidad para crecer por bioconversión en un amplio rango de materiales lignocelulósicos (Fayssal et al, 2021). (Mahadevan & Shanmugasundaram, 2018), reporto valores similares, en el Efecto comparativo de diferentes medios de cultivo sobre el rendimiento del crecimiento micelial de Pleurotus sapidus, 7.72 cm, en un medio Yeast Malt Agar, a los 8 días de cinética de crecimiento radial.…”

Olive and green tea leaves extract in Pleurotus ostreatus var. florida culture media: Effect on mycelial linear growth rate, diameter and growth induction index

“…This may point the role of tea extract when combined with olive leaves one in the hastening of mycelial growth. Green tea extract contains valuable enzymes [26] that may have been liberated and thus helped in the decomposition of holocellulose compounds (found in olive and tea extracts) and the provision of needed energy for P. ostreatus mycelium growth [9,10].…”

“…It is ranked as the second most cultivated mushroom in the world [8] and is well known for its high nutritional value (carbohydrates, protein, minerals) and medicinal properties (vitamins and antioxidants) [9]. It is mainly grown on wheat straw substrate [10,11] beside many other substitutes like spent mushroom substrate (SMS) [12,13], spent coffee grounds [14], maize wastewater [15], tea leaves [16] and so on. It is noteworthy that the type of substrate affects majorly the yield and composition of produced mushrooms [17,18].…”