title: Optimization of High Solids Dilute Acid Hydrolysis of Spent Coffee Ground at Mild Temperature for Enzymatic Saccharification and Microbial Oil Fermentation.
abstract: Soluble coffee, being one of the world's most popular consuming drinks, produces a considerable amount of spent coffee ground (SCG) along with its production. The SCG could function as a potential lignocellulosic feedstock for production of bioproducts. The objective of this study is to investigate the possible optimal condition of dilute acid hydrolysis (DAH) at high solids and mild temperature condition to release the reducing sugars from SCG. The optimal condition was found to be 5.3 % (w/w) sulfuric acid concentration and 118 min reaction time. Under the optimal condition, the mean yield of reducing sugars from enzymatic saccharification of defatted SCG acid hydrolysate was 563 mg/g. The SCG hydrolysate was then successfully applied to culture Lipomyces starkeyi for microbial oil fermentation without showing any inhibition. The results suggested that dilute acid hydrolysis followed by enzymatic saccharification has the great potential to convert SCG carbohydrates to reducing sugars. This study is useful for the further developing of biorefinery using SCG as feedstock at a large scale.
authors.affiliation: Department of Fragrance and Cosmetic Science, Kaohsiung Medical University, Kaohsiung, 80708, Taiwan.
authors.forename: Hui-Min David
authors.initials: HD
authors.lastname: Wang
authors.affiliation: Department of Chemical and Materials Engineering, National Yunlin University of Science and Technology, Douliou, Yunlin, 64002, Taiwan. yscheng@yuntech.edu.tw.
authors.forename: Yu-Shen
authors.initials: YS
authors.lastname: Cheng
authors.affiliation: Department of Chemical and Materials Engineering, National Yunlin University of Science and Technology, Douliou, Yunlin, 64002, Taiwan.
authors.forename: Chi-Hao
authors.initials: CH
authors.lastname: Huang
authors.affiliation: Department of Chemical and Materials Engineering, National Yunlin University of Science and Technology, Douliou, Yunlin, 64002, Taiwan.
authors.forename: Chia-Wei
authors.initials: CW
authors.lastname: Huang
mesh_terms: D000704:Analysis of Variance; D001419:Bacteria / Q000378:metabolism*; D018533:Biomass; D050260:Carbohydrate Metabolism / Q000187:drug effects*; D002241:Carbohydrates / Q000032:analysis; D002480:Cellulase / Q000378:metabolism*; D003069:Coffee / Q000737:chemistry*; D005285:Fermentation / Q000187:drug effects*; D006868:Hydrolysis; D008962:Models, Theoretical; D009821:Oils / Q000378:metabolism*; D013464:Sulfuric Acids / Q000494:pharmacology*; D013696:Temperature; D014866:Waste Products
chemical_list: D002241:Carbohydrates; D003069:Coffee; D009821:Oils; D013464:Sulfuric Acids; D014866:Waste Products; D002480:Cellulase; C033158:sulfuric acid
keywords: Dilute acid hydrolysis; Enzymatic saccharification; Fermentable sugars; High solids; Microbial oil; Mild temperature; Spent coffee ground