Hydrolytic Performance of Aspergillus niger and Trichoderma reesei Cellulases on Lignocellulosic Industrial Pineapple Waste Intended for Bioethanol Production

Abstract

The hydrolytic action of Aspergillus niger and Trichoderma reesei commercial cellulases, alone or combined with A. niger hemicellulase, against industrial pineapple waste as a previous step to produce bioethanol was investigated. Methods Enzymatic hydrolysis experiments were conducted in static conditions in an incubation oven, by adding the corresponding enzyme mixture to the pineapple waste (combinations of 0, 0.1, 0.2 and 0.4 (w/w) of cellulase from A. niger or T. reesei and hemicellulase from A. niger). pH and total soluble solids were examined along the treatments, and the sugar profile in the final hydrolysates was evaluated by High-Performance Anion-Exchange Chromatography. Results T. reesei cellulase exhibited a significantly faster initial hydrolysing rate than A. niger cellulase (0.258±0.004 vs. 0.15±0.07, for the maximum enzyme concentrations assayed), although differences regarding soluble sugars increments were not significant at the end of the treatment (0.349±0.009 vs. 0.34±0.05). Glucose, fructose, sucrose, arabinose, xylose and cellobiose were identified in the hydrolysates. Increasing enzyme concentration (cellulase or hemicellulase) produced an increase in total and fermentable sugars released (17 and 11%, respectively, for the maximum enzymatic concentration assayed); besides, a synergistic effect of combining hemicellulase and cellulase was identified. Accumulation of cellobiose (up to 4.4 g/L), which may slow down hydrolysis, evidenced the weaker β-glucosidase activity of T. reesei cellulase. Due to its performance and the lower cost of the enzyme, A. niger cellulase was chosen as an alternative. Conclusions 2 Commercial A. niger cellulase represents an efficient alternative to T. reesei cellulase for the saccharification of industrial pineapple waste, especially when combined with a hemicellulase. Total sugars present in the final hydrolysates indicated that A. niger cellulase performed similarly at a lower cost, with no cellobiose accumulation. However, if processing time is a limiting factor, Trichoderma reesei cellulase could be the one preferred.

Evaluation of Persimmon (Diospyros kaki Thunb. cv. Rojo Brillante) Industrial Residue as a Source for Value Added Products

“…According to previous investigations in other lignocellulosic matrices to which similar enzyme loads had been added and similar process conditions had been applied [24,26], hydrolytic action of enzymes is expected to have finished after 24 h of treatment. In the present study, a significant increase in bioethanol production during the first 24 h of treatment was observed, which continued up during the 72 hours registered, albeit at a much slower pace than previously.…”

“…Bioethanol production from lignocellulosic biomass usually involves two stages that can be carried out consecutively or simultaneously: the hydrolysis of cellulose and hemicellulose into mono and di-saccharides and the fermentation of the resulting sugars to obtain bioethanol. Hydrolytic enzymes used in the saccharification stage are usually obtained from fungi and consist of cellulases, which hydrolyze cellulose firstly into small oligosaccharides and then into glucose; and hemicellulases, which hydrolyse hemicellulose into monomeric sugars [24]. Simultaneous saccharification and fermentation (SSF) provides higher ethanol yield and lower energy consumption but usually requires higher concentration of enzymes, since control parameters are maintained closer to the optimum for fermentation than the optimum for enzymes performance [25,26].…”

Use of wastes from the tea and coffee industries for the production of cellulases using fungi isolated from the Western Ghats of India

“…Cellulases are some of the most used enzymes at the industrial level due to the wide range of activities in which they can be used, including the production of livestock feed, in the paper industry [18], detergent production [19], renewable energy generation [20], among others. These enzymes are commonly produced at an industrial level using filamentous fungi, because they produce the most complex enzyme pools and have a high secretion capacity [21].…”