Solid-State Fermentation of Orange Peels for Recovery of Orange Oil Using Aspergillus species NCIM 1432

The available orange peel extraction processes have several drawbacks including the need of solvents and high temperatures which affect the quality of orange oil. Thus there is a need to develop an alternate green process for extraction of orange oil. In present study, solid state fermentation (SSF) of fresh orange peels by Aspergillus species NCIM -1432 to extract extra-cellular enzymes and orange peel oil are noted. Additionaly, the effect of methods of orange peel sterilisation, importance of selection of the fermentation strain, effect of external nitrogen source, and particle size of the peels are detailed. The process used here gave 0.95 % w/w yield of orange oil. The color of the extracted oil is noted with 56.8, 4.7 and 12.2 CIE L*a*and b* values respectively typical to the orange colour. Also, the oil has been noted with typical orange fruit aroma. Further, the chemical composition of the extracted oil has been monitored by GC-MS, HPLC –MS which showed 96 % w/w limonene content. The oil is noted with anti-oxidant property upon its DPPH assay, with 0.87 of specific gravity. All the properties of the oil indicate a good quality oil. The crude hydrolytic enzymes produced during fermentation showed 155 U. g-1 and 239 CMC. g-1 of pectinase and cellulase activity respectively. The developed method of orange oil extraction is green, needs low tech equipment and can be an alternative to the available orange peel oil extraction methods at small scale.