Oligosaccharide production from coffee wastes and extracts by fermentation

With fermentation, many products with high added value can be produced using different microorganisms and carbon sources. In this study, inulinase and β-mannanase enzymes were produced by solid state fermentation (SSF) using Aspergillus niger A42 (ATCC 204447) and recombinant Aspergillus sojae AsT3 (ATCC 11906). SSF is being used for its advantages like utilizing wastes from food and agricultural industries, for being responsible for the growth of microorganisms on moist solids in nature, less wastewater, more economic and for being an easy method etc. Coffee is one of the most consumed drinks in the World and the waste of coffee cannot be evaluated sufficiently. Therefore, it is aimed to produce enzymes and oligosaccharides by using coffee waste, ground coffee and coffee extract. Plackett-Burman Design (PBD) was used to create a design for enzyme production with 4 different parameters that were selected as pH, solid:liquid ratio, mix ratio (coffee waste and ground coffee) and temperature. Oligosaccharide production was carried out by enzymatic hydrolysis using inulinase and β-mannanase enzymes obtained as a result of PBD design, and the amount and profiles of fructooligosaccharide (FOS) and mannooligosachharide (MOS) were determined. The highest inulinase activity was found to be 564,065±2,636 U/mg from the conditions of 8 pH, 1:4 solid:liquid ratio, 1:1 mix ratio and 30°C. When the statistical analysis results were examined, it was seen that the temperature was statistically significant (P<0.05) for the production of inulinase enzyme. When the results of FOS production were examined, 1,1,1-kestopentaose was found in only 1st, 5th, 6th, and 10th runs. The highest 1,1,1-kestopentaose was found to be 38,341 ppm from the 5th run. It was observed that the amount of FOS obtained from runs 1, 5, 6 and 10 increased as to the control coffee sample. The highest β-mannanase activity was found to be 71,174±19,670 U/mg from the conditions of 4 pH, 1:2 solid:liquid ratio, 1:1 mix ratio and 30°C. When the statistical analysis results were examined, it was seen that the temperature was statistically significant (P<0.05) for the production of β-mannanase. As a result of MOS production, the highest mannobiose was found to be 109,662 ppm from run 8, the highest mannotriose was found to be 101,112 ppm from run 6, the highest mannotetrose was found to be 391,016 ppm from run 8 and the highest total MOS was found to be 600,644 ppm from run 8. When the control coffee samples were examined for FOS and MOS production, it was seen that the amount of FOS and MOS could be increased and the prebiotic activity of the coffee could be improved.