Co-Substrating of Peanut Shells with Cornstalks Enhances Biodegradation by Pleurotus ostreatus

Abstract

IntroductionPeanut shells (PS) are abundant agro-industrial waste products that are recalcitrant to degradation under natural conditions [1]. The increasing expansion of peanut production has led to accumulation of large quantities of these shells all over the world. In the US alone, peanut production increased by 45% between 2011 and 2012, bringing production to 3.04 million metric tons [2]. Globally, 45.6 million metric tons of peanuts are produced annually [3]. It has been estimated that for every kg of peanuts produced, 230-300 g of peanut shells are generated [4]. Therefore, as much as 13.7 million metric tons of peanut shells are churned out every year, most of which are dumped into the environment or burned [5,6]. Peanut shells are a renewable resource that could be targeted for purposeful use in the food, feed, paper and bioenergy industries. However, as yet, few if any value-added uses exist for them [7].Over the years, various attempts to utilize peanut shells have been made. Small fractions were incorporated into animal feed, especially for cattle [8], while some authors have experimented on their use as dietary fiber for humans [9]. Other non-food research trials include uses in pulp production [10], feedstock for bioethanol production [11,12], particle board component [13], mulch and activated charcoal [7]. However, the major drawback to their use in large scale industrial operations is the high lignin content.Much like other agricultural lignocellulolysic biomass, peanut shells are composed mainly of lignin, cellulose and hemicellulose. Lignin, a complex polymer, is the most recalcitrant component of plant biomass [14] and binds tightly to, and provides a physical seal around, cellulose and hemicellulose [11,[15][16][17][18], thereby protecting them against attack by hydrolytic enzymes. The restricted bioavailability of these sugars and other components is thought to be largely physical, with lignin molecules reducing the surface area available to enzymatic penetration and activity [19]. In order to gain access to the sugars in cellulose and AbstractWorld consumption of peanuts has increased tremendously, resulting in abundance of peanut shell waste. The high lignin content of peanut shells limits their bioconversion to useful products or recycling. Therefore, the synergy in co-substrating peanut shells (PS) and cornstalks (CS) to enhance biodegradation was evaluated. Various compositions of peanut shells and cornstalks (% dry weight) herein called co-substrate -90PS:10CS, 75PS:25CS, 50PS:50CS, 25PS:75CS, 10PS:90CS, and two controls Cont1-100PS and Cont2-100CS were studied under solid state fermentation (SSF) with a white rot fungus, Pleurotus ostreatus for 120 days. A two-factorial experiment in a completely randomized design (CRD) was used. Results showed that substrate composition and fermentation time were important variables in substrate degradation. Lignin degradation, losses in organic matter, cellulose and hemicellulose increased with time. Increasing the composition of CS in co-substrates...

Ligninolytic enzymes production during polycyclic aromatic hydrocarbons degradation: effect of soil pH, soil amendments and fungal co-cultivation

“…Kiwi peels contain 53.73% of carbohydrates, 3.84% of protein, 6.93% of soluble and 18.92% of insoluble dietary fibres (Soquetta et al 2016), 25.26% of lignin (Gençer 2015), free sugars and fatty acids (Dias et al 2020), besides higher mineral content than their respective edible parts (Soquetta et al 2016). Peanut shells are rich in many functional compounds as cellulose, hemicellulose and lignin (Duc et al 2019), in which lignin can represent up to 41.3% of the lignocellulose, being this value 2 to 4 times higher than for most common agricultural residues, such as rice straw, wheat straw, sugarcane bagasse and corn cob/stover (Anike et al 2016).…”

Protein fraction, mineral profile, and chemical compositions of various fiber-based substrates degraded by Pleurotus ostreatus

“…These results confirm that when using substrates rich in lignin such as oat and barley straw, biodegradation is limited and the strain plays an important role in the ability to produce enzymes that allow it to degrade lignin. This makes it possible to access the sugars present in hemicellulose and cellulose in order to take advantage of them as energy sources during the colonization of the substrate and its subsequent fruiting (Anike et al 2016). Pleurotus ostreatus is a white rot fungus identified as a species capable of improving the nutritional conditions of lignocellulosic materials because of its high selectivity for degrading lignin (Van Kuijk et al 2015).…”

Immobilizing white‐rot fungi laccase: Toward bio‐derived supports as a circular economy approach in organochlorine removal

“…sanguineus (Thota et al, 2018), P. ostreatus (Akinfemi, 2010;Anike et al, 2016;Mishra & Kumar, 2007;Zervakis et al, 2001), P. pulmonarius (Akinfemi, 2010;Zervakis et al, 2001) 2022). The high amounts of polyphenols in PS (Adhikari et al, 2019;Han et al, 2022;Hassan et al, 2021;Win et al, 2011) could have a positive effect on Lac stability.…”

“…On the other hand, PS proved to be an excellent substrate for the growth of WRF Pleurotus eryngii, Agrocybe aegerita , Auricularia auricula‐judae , Lentinula edodes and Volvariella volvacea (Zervakis et al, 2001), P. sanguineus (Thota et al, 2018), P. ostreatus (Akinfemi, 2010; Anike et al, 2016; Mishra & Kumar, 2007; Zervakis et al, 2001), P. pulmonarius (Akinfemi, 2010; Zervakis et al, 2001), and Trametes hirsute (Rodriguez‐Couto & Sanromán, 2006) under solid‐state fermentation. Cultivation of WRF under optimized fermentation growth conditions using PS as a substrate for Lac production was performed by Mishra and Kumar (2007); Rodriguez‐Couto and Sanromán (2006); Irshad et al (2012); Nasreen et al (2015); Liu et al (2018); and Chmelová et al (2022).…”