Solid‐state fermentation for the production of a recombinant β‐mannanase from Aspergillus fumigatus expressed in Aspergillus sojae grown on renewable resources

Abstract

In this study, not only beta (β)-mannanase fabrication by recombinant Aspergillus sojae AsT3 in solid-state fermentation (SSF), but also the mannooligosaccharide (MOS) production was investigated. Barley husk, wheat bran, rye bran, oat husk, and spent coffee grounds were used as substrates. Plackett–Burman design was used to optimize SSF conditions (temperature, time, inoculation rate, and pH) based on enzyme activity and MOS results. While the highest β-mannanase activity was found to be 983.53 U/mg in rye bran samples, it was found to be 582.59 U/mg, 55.59 U/mg, and 413.50 U/mg for the barley husk, wheat bran, and oat husk, respectively. The highest enzyme activity and MOS production were found to be 255.82 U/mg and 1,079.785 ppm with 7% inoculation rate, 30°C, 7 days and pH 7. Results showed that SSF is suitable for β-mannanase and MOS production due to the evaluation of wastes, lower energy requirement, and suitable environment for growth. Practical applications Evaluation of all kinds of agricultural products and waste is an economical alternative source for biotechnological applications. The β-mannanase enzyme is widely used in many fields, from the coffee industry to the paper industry, from cleaning products to animal feed production. Mannooligosaccharides (MOS) are water-soluble dietary fibers and are not digested by humans. Members of this group are used by the intestinal microflora as nutrients and create useful substances for human health. When mannans are partially disintegrated by the enzyme β-mannanase, MOS that can be used as a substrate by microorganisms is produced. Therefore, the production of MOSs is one of the usage areas of the β-mannanase enzyme. In this study, β-mannanase production was carried out by using the SSF process. This process was successful to produce the enzyme and MOS. Besides, as no pretreatment is made to the carbon sources used in enzyme production, time and energy are saved.