Co‐Cultivation of Aspergillus niger and Trichoderma reesei Enables Efficient Production of Enzymes for the Hydrolysis of Wheat Bran

Abstract

Agro‐residues like wheat bran may be a useful carbon source for fermentation processes. However, due to their composition, hydrolysis appears complex. A co‐cultivation process was established with the two fungi A. niger and T. reesei for the production of an adapted mixture of enzymes for hydrolysis. This enzyme solution reached a higher space‐time yield of sugars during the hydrolysis of wheat bran compared to enzymes from respective monocultures, demonstrating the potential of this co‐culture for the production of complementary enzyme mixtures for the hydrolysis of wheat bran.

Valorization of Wheat Bran by Co-Cultivation of Fungi with Integrated Hydrolysis to Provide Sugars and Animal Feed

“…The end of the enzyme production was indicated by a rapid increase in DO due to the depletion of nutrients. At this point, the temperature was increased to a hydrolysis temperature of 50 °C, which was shown previously to be the optimal temperature for the present enzyme mixture [ 31 ]. Simultaneously, the agitation rate was set to 550 min −1 , the pressure was reduced to atmospheric pressure, and the aeration rate was lowered to the minimum value of 5 L min −1 to prevent blockage of the sparger by biomass particles.…”

“…Total xylanase, amylase, and cellulase activities were determined by colorimetric assay using 4-hydroxybenzhydrazide (pHBAH), following a protocol previously described [ 31 ] measuring the sugar release from xylan, starch, and carboxymethyl cellulose (CMC), respectively. Activities of each sample were determined in triplicate and results were depicted as means with respective standard deviations.…”

“…As the production of all necessary enzymes in several separate processes would be extremely labor- and cost-intensive [ 28 ], the co-cultivation of the respective microorganisms poses a promising alternative approach to produce the desired enzyme mixture [ 29 , 30 ]. In an earlier study, we reported the establishment of such a co-culture consisting of the two filamentous fungi Aspergillus niger and Trichoderma reesei for the hydrolysis of wheat bran [ 31 ]. The ascomycete A. niger has been one of the most researched and applied microorganisms in biotechnology and is well-known for its capability to produce several enzymes as well as organic acids [ 32 , 33 , 34 ].…”

“…In the case of the degradation of lignocellulosic materials like wheat bran, especially the xylanases and amylases produced by A. niger are of great interest. A. niger NRRL 2270 (ATCC 11414), which was used in the presented work, stems from a citric acid-producing strain [ 35 ], but nevertheless, a high potential regarding the enzymatic degradation of plant material has been observed and reported [ 31 , 36 ]. This strain was partnered with T. reesei , which is known for its high capability for cellulase formation and secretion [ 37 , 38 ].…”

“…This deficiency can be compensated by other microorganisms, including A. niger. Overall, the production of xylanases, amylases, and β-glucosidase by A. niger NRRL 2270, combined with the cellulase hypersecretion of T. reesei RUT-C30, results in a complementary and adapted enzyme mixture to hydrolyze wheat bran [ 30 , 31 , 48 , 49 , 50 , 51 , 52 ].…”