부산대학교 도서관

Olive oil industry is a growing industrial sector in Mediterranean countries. Unfortunately, about 30–35% of total olive weight is discarded as olive pomace (OP), a highly environmental-polluting solid waste. OP is mostly used for composting and production of animal feed; nevertheless, the high oil content, phenolic compounds and fiber contents in addition to its low protein content represent major obstacles for both applications. So, the present study was conducted to evaluate the role of solid state fermentation (SSF) in OP using Kluyveromyces marxianusNRRL Y-8281 yeast on the chemical composition and tannin content of OP in a trial for its bioconversion into a value-added animal feed. Chemical composition, nutritive and energetic values, tannin and gallic acid contents of unfermented and fermented olive pomace were investigated. The fermentation altered the chemical composition of OP, so that crude fiber was decreased by 8.56%, while crude protein, fat and carbohydrate contents were increased by 2.74, 2.63 and 3.57%, respectively. Moreover, the effect of fermentation on cell wall constituents, gross energy, digestible energy, total digestible nutrients and digestible crude protein was evaluated. Furthermore, HPLC analysis revealed that K. marxianusmediated fermentation of OP resulted in a sharp decrease in tannin content by 96.75% with 2.8 times increase in gallic acid concentration. SSF of OP by K. marxianusdoes not only eliminate the environmental pollution resulting from its accumulation, but also presents a new eco-friendly valorization technique which leaves OP with an altered chemical composition allowing its use as animal feed or compost.