Effect of microwave pretreatment of mixed culture on biohydrogen production from waste of sweet produced from Benincasa hispida

•Benincasa hispida waste has been taken as the substrate which is dumped untreated.•Microwave pretreatment of inoculum for 5 min each at different powers.•14 mmol H2 per mol soluble sugar was obtained when inoculum was pretreated at 320 W.•Optimum HAc/HBu was 1.11 in the reactor pretreated at 320 W for 5 min.•Butyrate type of fermentation took place.

To enhance the production of biohydrogen from biomass, various pretreatment methods play important role. In this study, effect of microwave irradiation on the culture was studied on biohydrogen production from Benincasa hispida (Petha) solid waste at different powers for a fixed interval of time. The highest power studied was 800 W with a frequency of 2450 MHz. The amount of soluble sugars found in the waste was 13.9 mg/L having the chemical oxygen demand (COD) of 3000 mg/L. Studies have been performed in batch reactors using mixed consortia and results were also compared with the reactor operated at the normal conditions i.e. without any inoculum pretreatment. Maximum hydrogen produced was 14 mmol H2 per mol of soluble sugar consumed in the reactor in which the inoculum was exposed to 320 W of microwave for 5 min. SEM analysis of this microwave pretreated culture was done.

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