Bio-based fractions by hydrothermal treatment of olive pomace: Process optimization and evaluation

•Olive pomace was utilized based on biorefinery concept.•Protein extraction in the high pressure reactor yielded 231 mg protein/L.•LHW treatment followed by enzymatic hydrolysis yielded 93.7% of the fermentable sugars.•At the end of the consecutive steps, 94.4% of the lignin present in the biomass were recovered.•Obtained hydrolysate was further converted to bioethanol.

Olive pomace is an important lignocellulosic biomass for Mediterranean countries which is released in large quantities during industrial olive oil production and used for heating purposes for many years. In this study, the aim was to investigate the use of olive pomace to obtain value added fractions namely, proteins, fermentable sugars and lignin by sustainable biorefinery approach applying a sequence of high pressure extraction and hydrolysis. After pretreatment steps, 93.7% of the fermentable sugars and 94.4% of the lignin that present in the biomass were recovered. Liquid hot water (LHW) pretreatment was shown to enhance the yield of enzymatic hydrolysis by an increase of 95.23%. The obtained sugars were used to produce bioethanol and based on the consumed sugar the yield and productivity were determined as 15.25% and 0.086 kg/m3 h respectively.

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