Recycling durian shell and jackfruit peel via anaerobic digestion.

With growing popularity of durian and jackfruit, environment threats following improper management of durian shell (DS) and jackfruit peel (JP) are increasingly serious. Anaerobic digestion is a potential solution but concern on its unsatisfied efficiency from lignocellulosic recalcitrance remains. This work applied four representative pretreatments on DS and JP to determine the effects on methane generation, energy potential, and environmental benefits. The suitable pretreatments for DS and JP were 3% KOH and 5% AHP, causing 103.8% and 69.8% increase in methane yield and biodegradability than untreated, respectively. Moreover, 3% KOH-treated DS and 5% AHP-treated JP could potentially produce total energy of 2.0 × 109 MJ/year, reduce coal consumption by 6.8 × 104 ton/year, and cut emission by 2.2 × 1010 particulate/year, which might alleviate the serious energy crisis and environmental issues from the overuse of fossil fuel. This study provides important insights into efficient use of DS and JP, and a reference for other fruit wastes.

Effects of different microbial pretreatments on the anaerobic digestion of giant grass under anaerobic and microaerobic conditions.

Microbial pretreatment to lignocellulosic biomass for anaerobic digestion (AD) has achieved increased attention; however, the low efficiency and unclear mechanism of oxygen parameter affecting this process performance limit its practical application. In this study, five readily available microbial consortia were developed to analyze the influences of various oxygen concentrations during pretreatment process upon methane conversion efficiency and microbiota within AD of giant grass. Results found that anaerobic pretreatment by liquid or straw composting inoculant, along with microaerobic pretreatment by cow manure at 10 mL/g VS oxygen concentration, obtained 23.1%, 24.4%, and 16.0% higher methane yields (275.3, 279.8, and 265.3 mL/g VS) than corresponding untreated group, respectively. Microbial community analyses showed that microbial responses to oxygen varied significantly with microbial consortium, which consequently caused different AD performances. The findings will enrich theoretical knowledge of microbial pretreatment and provide a technological guidance for efficient utilization of giant grass and other lignocellulosic biomasses.