Improvement of biogas production from orange peel waste by leaching of limonene.

Rachma Wikandari,Claes Niklasson,Mohammad J Taherzadeh,Huong Nguyen,Ria Millati

doi:10.1155/2015/494182

Rachma Wikandari, Claes Niklasson + Show 3 more

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https://doi.org/10.1155/2015/494182

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Abstract

Limonene is present in orange peel wastes and is known as an antimicrobial agent, which impedes biogas production when digesting the peels. In this work, pretreatment of the peels to remove limonene under mild condition was proposed by leaching of limonene using hexane as solvent. The pretreatments were carried out with homogenized or chopped orange peel at 20–40°C with orange peel waste and hexane ratio (w/v) ranging from 1 : 2 to 1 : 12 for 10 to 300 min. The pretreated peels were then digested in batch reactors for 33 days. The highest biogas production was achieved by treating chopped orange peel waste and hexane ratio of 12 : 1 at 20°C for 10 min corresponding to more than threefold increase of biogas production from 0.061 to 0.217 m3 methane/kg VS. The solvent recovery was 90% using vacuum filtration and needs further separation using evaporation. The hexane residue in the peel had a negative impact on biogas production as shown by 28.6% reduction of methane and lower methane production of pretreated orange peel waste in semicontinuous digestion system compared to that of untreated peel.

Highlights

Orange as the main citrus fruit is one of top-five fruit commodities that dominate the global fruit market
The hexane residue in the peel had a negative impact on biogas production as shown by 28.6% reduction of methane and lower methane production of pretreated orange peel waste in semicontinuous digestion system compared to that of untreated peel
In the experiment to select the solvent, each solvent was added to the orange peel with orange peel waste and hexane ratio of 1 : 4. The mixture of solvent and orange peel was shaken vigorously for 10 minutes followed by incubation for 20 minute at room temperature

Summary

Introduction

Orange as the main citrus fruit is one of top-five fruit commodities that dominate the global fruit market. 40–60% of oranges are processed for juice production, of which 50–60% ends up as waste including seed, peel, and segment membrane [2, 3]. The generation of these solid wastes is estimated to be in the range of 15 to 25 million tons per year [3]. Among these wastes, citrus peel is the major constituent accounting for approximately 44% of the weight fruit mass [4]

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