Optimization of cultural conditions for protease production by a fungal species

Abstract

Studies were carried out on a paddy soil fungal isolate identified to be a strain of Aspergillus niger from Manipal. The parameters that largely impact enzyme production viz., fermentation time, impeller speed, pH, temperature and nutrient supplements were studied. Optimization of production parameters for production of protease was done by the single-parameter mode. Casein served as substrate and proteolytic activity was estimated using Folin-Ciocalteau method at 660 nm. A maximum yield of 71.3 mg tyrosine/g casein substrate was produced in 96 h on a soluble starch medium at pH 4 in shake flask experiments. Production was carried out on a 3-liter fermenter and 40.7 mg of tyrosine was liberated/g of substrate. The enzyme was extracted with 50% ammonium sulfate and sodium dodecyl sulfate-Polyacrylamide gel electrophoresis showed two bands having mw 45.7 kDa and 38.5 kDa, respectively. The enzyme activity was found to be 147.84 U/ml.

Production of α-Amylase by Aspergillus terreus NCFT 4269.10 Using Pearl Millet and Its Structural Characterization

“…Nwagu and Okoli (2011) also observed that a particular strain of Aspergillus fumigatus exhibited maximum mycelial yield and amylase titre at 30°C which is akin to the present findings (Figure 1A), however, the reports of Negi and Banerjee (2010) on A. awamori for production of amylase was not at par with the present finding. As compared to the present study conducted for effect of cultivation time on production of amylase, similar result was reported by Negi and Banerjee (2010) for amylase biosynthesis using A. awamori . Mohamed et al (2011) reported 96 h and 30°C for biosynthesis of amylase which is in accordance with present finding.…”

“…Even though, the outcome of this study could not specify the genuine moisture content in the system, however, it gave a clue of the preliminary water content of PM which was essential to attain the maximum fungal growth and biosynthesis of enzyme. While working with Aspergillus species and A. awamori , Chimata et al (2010), Negi and Banerjee (2010) reported 70 and 90% humidity for amylase production which is at par with the present finding obtained with A. terreus NCFT 4269.10.…”

“…Somehow, Negi and Banerjee (2010) have studied the influence of supplementary carbon sources for amylase biosynthesis and concluded that starch displayed enhanced production of amylase. This is not at par with the present findings.…”

“…Similarly, as reported by Afifi et al (2008) the water soluble vitamin C (tocopherols) was the most supportive vitamin for growth, generation of protein and production of α-amylase by P. olsonii which also relates to the effect of vitamins for enhanced production of α-amylase by A. terreus . Furthermore, Negi and Banerjee (2010) had also reported the function of different plant growth regulators on the production of α-amylase and protease by A. awamori and concluded that indol-3-acetic acid (IAA) and Indole-3-butyric acid (IBA) enhanced the biosynthesis of enzymes secreted by A. awamori . The findings of Negi and Banerjee (2010) reported that napthelene acetic acid (NAA) and 2-4, D enhanced protease production but retarded biosynthesis of amylase which was also reported with the findings of A. terreus .…”

“…and Rhizopus spp., probably due to their ubiquity and non-pretentious nutritional requirements. Substrates like vegetable waste, rice husk, banana peels (Khan and Yadav, 2011), wheat bran (Negi and Banerjee, 2010), date wastes (Acourene and Ammouche, 2012), sugarcane baggase (Roses and Guerra, 2009), wheat straw, rye straw, corncob leaf, oil cakes, and many others (Bhargav et al, 2008) have been utilized for the biosynthesis of amylases. Consequently, SSF process is of particular economic concern for such countries which have generation of huge plant biomass and agro-industrial wastes.…”