Process Optimization for Citrus Waste Biorefinery via Simultaneous Pectin Extraction and Pretreatment

BioResources

Jonny Palhed¹  Keikhosro Karimi²  Mohammad J. Taherzadeh³  Magnus Lundin⁴  Akram Zamani⁵  Behzad Satari⁶ 

[1] Department of Chemical Engineering, Isfahan University of Technology, Isfahan 84156-83111, Iran;Iran, Islamic Republic Of;Sweden;Swedish Centre for Resource Recovery, University of Borås, 50190 Borås, Sweden;Department of Chemical Engineering, Isfahan University of Technology, Isfahan 84156-83111, Iran;Swedish Centre for Resource Recovery, University of Borås, 50190 Borås, Sweden;

关键词: Citrus waste;    Dilute-acid;    Enzymatic hydrolysis;    Ethanol;    Fermentation;    Full factorial design;    Fungal biomass;    Limonene;    Mucor indicus;    Pectin;    Pretreatment;   

DOI  :  10.15376/biores.12.1.1706-1722

来源: DOAJ

【 摘 要 】

In a novel valorization approach for simultaneous pectin extraction and pretreatment (SPEP) of citrus waste (CW) by dilute nitric acid and ethanol, almost all of the CW was converted to bio-derived chemicals in a single-step process at a low/moderate temperature. The SPEP was performed at different temperatures (70 °C and 80 °C), pH (1.8, 3.0, and 4.3), and extraction times (2 h and 3 h) with a full factorial design. The maximum pectin yield of 45.5% was obtained at pH 1.8, 80 °C, and 2 h. The pectin yields at pH 1.8 were much higher than at pH 4.3 and 3. Also, the degree of methyl-esterification at pH 1.8 was higher than 50%, whereas at the higher pH, low methoxyl pectins were extracted. The treated CW obtained after the SPEP, free from limonene, was subjected to separate cellulolytic enzymatic hydrolysis and ethanolic fermentation. The glucose yields in the enzymatic hydrolysates were higher for the CW treated at pH 1.8. The fermentation of the enzymatic hydrolysates by Mucor indicus resulted in fungal biomass yields in the range of 355 to 687 mg per g of consumed sugars. The optimum conditions for obtaining the maximum SPEP yield (glucose + pectin (g) / raw material (g))*100) were pH 1.8, 80 °C, and 2 h, which resulted in a yield of 58.7% (g/g CW).

【 授权许可】

Unknown