Production of tyrosinase by Auricularia auricula using low cost fermentation medium
Low cost fermentation media using agricultural by-products (wheat bran extract, rice bran extract and soybean meal extract) as a major nutrient source, were evaluated for the production of tyrosinase from the fungus Auricularia auricula in submerged culture. In single-factor experiments, three components (wheat bran extract, casein and CuSO4) were chosen to further optimize medium composition using response surface methodology (RSM). The central composite experimental results showed the following optimum medium composition: wheat bran extract 36.0 %, casein 1.1 g/l and CuSO4 0.13 g/l. Under these conditions, the highest tyrosinase activity was 17.22 U/ml, which was 2.1 fold higher than that obtained using the non-optimized medium. The present study is the first to report the statistical optimization of medium composition for production of tyrosinase by A. auricula using cheaper wheat bran extract as a major nutrient source. These results might provide a reference for the development of a cost-effective medium for commercial production of tyrosinase.
Evaluation of crocin and curcumin affinity on mushroom tyrosinase using surface plasmon resonance.
Tyrosinase inhibitors have potential applications in the cosmetics and food industries for preventing browning reactions and also as therapeutic drugs for neurodegenerative diseases such as Parkinson's. In this article, crocin and curcumin were evaluated as mushroom tyrosinase inhibitors. Results showed that, both compounds strongly inhibited the diphenolase activity than monophenolase. The IC50 values for diphenolase activity were estimated to be 0.11 mM and 0.18 mM for crocin and curcumin respectively. The binding kinetics of crocin and curcumin was studied with mushroom tyrosinase using surface plasmon resonance (SPR). Tyrosinase was immobilized on the gold surface of a Biacore sensor chip through amine coupling. Binding of inhibitors was analyzed by SPR without the need to further modify the surface or the use of other reagents. The binding constant KD (M) for mushroom tyrosinase obtained was 1.21×10(-4) M for crocin and 1.64×10(-4) M for curcumin, while showing a higher affinity for L-DOPA 1.95×10(-8) M, a substrate for tyrosinase (positive control). The study reveals the SPR sensor's ability to detect binding of the inhibitors.
Influence of Diluted Spent Wash of Sugar Industries Application on Yield of and Nutrient Uptake by Sugarcane and Changes in Soil Properties
A pot experiment was conducted to study the effect of irrigation with tube well water (S0) as well as with spent wash diluted for 25 (S25), 50 (S5O) and 100 (S100) times on yield of and nutrient uptake by sugarcane grown on Typic Chromustert. The results revealed that application of spent wash diluted at any level increased the sugarcane yield and nutrient uptake significantly over S0. Less diluted spent wash gave higher yield of biomass than the concentrated one. Though, there was tendency for slight increase in the soil salinity due to use of spent wash, yet the nutrient availability of P, K and S increased considerably. Further, there was indication of betterment in some physical conditions of soil.