Enzymatic Hydrolysis of Spent Coffee Ground T. Jooste & M. P. García-Aparicio & M. Brienzo & W. H. van Zyl & J. F. Görgens Received: 16 March 2012 / Accepted: 6 February 2013 / Published online: 24 February 2013 # Springer Science+Business Media New York 2013 Abstract Spent coffee ground (SCG) is the main residue generated during the production of instant coffee by thermal water extraction from roasted coffee beans. This waste is composed mainly of polysaccharides such as cellulose and galactomannans that are not solubilised during the extraction process, thus remaining as unextractable, insoluble solids. In this context, the application of an enzyme cocktail (mannanase, endoglucanase, exoglucanase, xylanase and pectinase) with more than one component that acts synergistically with each other is regarded as a promising strategy to solubilise/hydrolyse remaining solids, either to increase the soluble solids yield of instant coffee or for use as raw material in the production of bioethanol and food additives (mannitol). Wild fungi were isolated from both SCG and coffee beans and screened for enzyme production. The enzymes produced from the selected wild fungi and recombinant fungi were then evaluated for enzymatic hydrolysis of SCG, in comparison to commercial enzyme preparations. Out of the enzymes evaluated on SCG, the application of mannanase enzymes gave better yields than when only cellulase or xylanase was utilised for hydrolysis. The recombinant mannanase (Man1) provided the highest increments in soluble solids yield (17 %), even when compared with commercial preparations at the same protein concentration (0.5 mg/g SCG). The combination of Man1 with other enzyme activities revealed an additive effect on the hydrolysis yield, but not synergistic interaction, suggesting that the highest soluble solid yields was mainly due to the hydrolysis action of mannanase. Keywords Coffee bean . Spent coffee ground . Cellulose . Mannan . Cellulase . Mannanase . Water extraction Introduction Spent coffee ground (SCG) is the main insoluble residue generated during the production of soluble instant coffee by thermal water extraction from roasted coffee beans [1]. A flow Appl Biochem Biotechnol (2013) 169:2248–2262 DOI 10.1007/s12010-013-0134-1 T. Jooste : M. P. García-Aparicio : M. Brienzo (*) : J. F. Görgens Department of Process Engineering, Stellenbosch University, Private Bag X1, Stellenbosch 7602, South Africa e-mail: michelbrienzo@yahoo.com.br W. H. van Zyl Department of Microbiology, Stellenbosch University, Private Bag X1, Stellenbosch 7602, South Africa