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[Display omitted] • Spent Substrate of Pleurotus ostreatus can act as potential biomass for biobutanol production. • Clostridium acetobutylicum MTCC 11274 produced ABE concentration of 10.80 ± 0.02 g/L. • Hybrid pre-treatment showed maximum biobutanol yield of 0.38 g/g. • SEM, FT-IR, XRD data confirmed the breakdown of lignin and hemicellulose. Addressing global energy demand, researchers sought eco-friendly biobutanol production from lignocellulosic waste biomass. In the present research work, five different pre-treatment methods viz., Microwave, Ultrasound, Alkali, Acid, and Hybrid, were investigated to explore its biobutanol production potential by utilizing Pleurotus ostreatus spent as substrate. The compositional and physico-chemical changes of the pre-treated Spent Mushroom Substrate (SMS) were assessed using SEM, FTIR, and XRD. Hybrid pre-treatment (Microwave, Alkali, Ultrasound) showed higher delignification when compared to conventional pre-treatment method. Hybrid pre-treated SMS resulted in higher total reducing sugars (521.53 ± 1.84 mg/g) than indigenous SMS (267.89 ± 1.53 mg/g). Fermentation of hybrid pre-treated SMS with Clostridium acetobutylicum MTCC 11274 produced the highest biobutanol concentration (9.84 ± 0.03 g/L) and yielded 0.38 ± 0.02 g/g of biobutanol. This study revealed that hybrid pre-treatment could be a promising solution for enhanced biobutanol production using SMS biomass. [ABSTRACT FROM AUTHOR]

Lignocellulosic wastes are generally pre-treated to facilitate the hydrolysis stage during the anaerobic digestion process. A process consisting of solid state fermentation carried out by white rot fungi and anaerobic digestion was evaluated on corn stover to produce ligninolytic enzymes and biogas. The enzyme production was quantified every 3 d for a month at 30 °C, and three fungal strains and two particle sizes of waste were compared. Of the main outcomes, Pleurotus eryngii produced the highest laccase enzyme activity compared with Pleurotus ostreatus and Trametes versicolor . Furthermore, this activity was improved by 16% when copper was used as an enzyme inducer. On the other hand, most of the conditions studied showed a decrease in maximum biogas production compared with untreated waste, the addition of copper decreased biogas production by 20%. Despite the above, Pleurotus eryngii showed promising results allowing a 19% increase of biogas production and high enzyme production values. [ABSTRACT FROM AUTHOR]

• For effective FR, iron-binding to wood was maximized through pH modification. • Optimum iron dosage was identified based on maximum methane production yield. • Up to 70 % of the methane produced in the first week for pretreated samples. • FR and fungal pretreatment of SEBW increased methane yield to 420 mL/gVS. • Simultaneous FR and fungal pretreatment reduced the lignin content by up to 25%. Delignification of steam-exploded birch wood (SEBW) was stimulated using a pretreatment method including Fenton reaction (FR) and fungi. SEBW was employed as a substrate to optimize the Fe(III) and Fe(II) dosage in FR. Maximum iron-binding to SEBW was obtained at pH 3.5. FR pretreatment increased biological methane yields from 257 mL/g vS in control to 383 and 352 mL/ g vS in samples with 0.5 mM Fe(II) and 1.0 mM Fe(III), respectively. Further enzymatic pretreatment using a commercial cellulase cocktail clearly improved methane production rate but only increased the final methane yields by 2–9 %. Finally, pretreatments with the fungi Pleurotus ostreatus (PO) and Lentinula edodes (LE), alone or in combination with FR, were carried out. SEBW pretreated with only LE and samples pretreated with PO and1 mM Fe(III) + H 2 O 2 increased the methane production yield to 420 and 419 mL/g vS respectively. These pretreatments delignified SEBW up to 25 %. [ABSTRACT FROM AUTHOR]

• The lignin degradation of combined bacteria is more significant than single bacteria. • The combined bacteria showed good correlation and coordination mechanism. • Best degrade conditions were TEMP 32 °C, pH 3.5, solid-liquid ratio 10%, for 20 days. In this study, the combined bacteria (CB) were constructed by Phanerochaete chrysosporium , Trametes versicolor and Pleurotus ostreatus , which have a good ability to degrade lignocellulose, and the optimum degradation conditions and internal degradation mechanism of combined bacteria were investigated. The results showed that under conditions of temperature (32 °C), pH (3.5), solid-liquid ratio (10%), culture time (20 d), the degradation rates of lignin, cellulose and hemicellulose were 43.36%, 31.29%, 48.36%, respectively. The construction of combined bacteria significantly enhances the degradation ability of lignocellulose, and showed good correlation and coordination mechanism. [ABSTRACT FROM AUTHOR]