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Trichoderma species have been famous for production of cellulases with relatively high enzymatic activity. However, attempts to use their cellulolytic enzymes in the bioconversion of cellulosic wastes have not been successful because of high cost of production and low enzymatic yields. This study aimed to obtain gamma-induced mutants of T. viride with enhanced extracellular cellulase production. Spore suspensions were exposed to γ-rays at 250 Gy as optimum dose. After irradiation, all germinated spores were grown onto PDA plates and mutant strains with better sporulation were selected and subcultured five times to test their stability. Cellulase activity was tested using Whatman No. 1 filter paper, carboxymethyl cellulose, avicel, bacterial cellulose and walseth cellulose according to the IUPAC recommendation. Extracellular proteins profiles of mutant strains were studied via SDS-PAGE. The maximum activity of total cellulase and avicelase were observed in the isolate of M21 (92.43 and 74.40 U/mg, respectively) and maximum endo-glucanase activity was observed in M18 mutant. The results of this study showed that the application of gamma ray led to a significant increase in Cellulose activity of 38 percent of mutant strains. Thus, this method could be used as a simple and efficient way to achieve strains with the ability to produce high levels of enzymes and other biological metabolites.
 

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S-layer proteins of Deinococcus radiodurans are the best self-assemble systems among other proteins that have an essential role in the fabrication of nanowires. Therefore, the purification of these proteins is necessary. The purpose of this research was to optimize the purification of s-layer protein from D. radiodurans with the response surface method. The three factors of SDS concentration, incubation time and mass percent in five levels were considered, and 20 runs were designed by Design-Expert software with a central composite method. Each run includes microbe culture, mass cell preparation, microbe incubation in specific SDS concentration and time and mass percent, separation of the bacteria from detergent with a centrifuge at 5000g, sedimentation of s-layer proteins from detergent solution with a centrifuge at 20000g, determination of protein concentration, and protein purity by Bradford and SDS-PAGE methods, respectively. Finally, the data obtained were analyzed.  Analysis of the results demonstrated that at the 95% confidence level, the effect of the detergent concentration factor on the purified protein percent was more than other factors. The optimization results of factors are 5.64% SDS concentration, 7.33% mass percent, and 3 hours incubation time. At optimized conditions the protein concentration and purity percent were obtained 0.584 mg/ml and 47.61% respectively.