Production of Glucoamylase, α-amylase and Cellulase by Aspergillus oryzae F-923 Cultivated on Wheat Bran under Solid State Fermentation

Abstract

<jats:p>Filamentous fungi have been widely utilized in production of enzymes which have many industrial applications. In this study, twenty five local fungal isolates, belonging to Aspergillus sp., Trichoderma sp. and Penicillium sp., were screened under solid state fermentation conditions (SSF) for the production of α-amylase, glucoamylase and cellulase. Asperigillus oryzae F-923, cultivated on wheat bran, was the most promising isolate for production of the target enzymes under this study. Physical parameters of moisture content, pH, temperature and incubation time, optimized were 1:2(w/v), 5.5, 28°C and 72 hr, respectively. The production of enzymes was enhanced when ammonium sulfate was supplemented as a nitrogen source to wheat bran. The production of α-amylase and glucoamylase was also enhanced when 10% (w/w) soluble starch was added as a carbon source to wheat bran. However xylose supplementation at 10% (w/w) was observed to be best for cellulase production. Tap water was found to be efficient for enzymes' extraction from the fermentation medium. Three successive extractions were needed to obtain the produced enzymes from the fermented substrate. Characterization of the produced enzymes revealed that, the optimum temperature for α-amylase and glucoamylase was 60°C, while 50°C was the optimum temperature for cellulase activity. Isopropanol 1:1(v/v) was proved to be more suitable for partial purification of enzymes. Following partial purification of enzymes of glucoamylase, α-amylase and cellulase increased to 10.8, 11.8 and 11.4 folds, respectively.</jats:p>

Production of Glucoamylase from Novel Strain of Alternaria Alternata under Solid State Fermentation

“…This could be related to the relative stability of glucoamylase at pH 5 ( Figure 6 ). These results were in line with the results of [ 4 ] as concentration of pH effect the growth of fungal strains and enzyme production was more adequate in acidic medium. In short, change in the pH level of media that is necessary for growth of fungal strains was directly related to the metabolic activity of enzyme.…”

“…Similarly, inoculum level of 0.5, 1, 1.5, 2, and 2.5 ml was used to study the fungal growth and enzyme production with spore count of 2.21 × 10 −7 , 4.42 × 10 −7 , 6.72 × 10 −7 , 9.27 × 10 −7 , and 11.43 × 10 −7 spores, respectively, and the 1 ml (4.42 × 10 −7 spores) of inoculum level among different levels of spore suspension showed the maximum specific activity of 36.0 U/mg and glucoamylase units of 15.5 ± 0.09 a U/ml/min) ( Figure 2 ) in the presence of selected media (10 g). In case of substrate concentrations, these results were parallel with the findings of [ 4 , 24 ] as the adequate amount of media was necessary for the maximum enzyme rate. Their results determined that the very low concentration of substrate is inefficient for growth of fungal strains due to less available nutrients and surface area for the growth of fungi and microbial enzymes to act upon it while more substrate thickness (higher amount of substrate) showed improper aeration and inadequate agitation that affects the aerobic conditions for fungal growth and decrease the enzyme production.…”

“…Hence, enzymes become inactive at inadequate pH level. So, the optimum pH is required for the proper growth of fungi and to get the highest yield of enzyme [ 4 ].…”

“…The sources of glucoamylase are animals, plants, and microorganisms [ 3 ]. Microbes like yeast, bacteria, and fungi are the cheapest source to produce glucoamylase [ 4 ]. The process is called microbial hydrolysis, and it is carried out on industrial wastes by these microbes.…”

The ancient koji mold (Aspergillus oryzae) as a modern biotechnological tool

“…3.2.1.1., 1,4-α-D-glucan glucanohydrolase) catalyze hydrolysis of internal α-1,4 glycosidic linkage in starch, amylopectin and amylose converting them into maltose and glucose. These enzymes are critically important especially in the detergent and the food industries (Brown Ramachandran et al (2004) utilized different oil cakes which are the byproducts obtained after oil extraction, while Fadel et al (2020) utilized wheat bran, corn flour, sugar beet pulp, sun flower for α-amylase production by A. oryzae. Glucoamylases are generally used in high fructose corn syrup, glucose syrup, and alcohol production (James and Lee 1997;Biesebeke et al 2005).…”