Aims: To optimize laccase production by submerged fermentation using an edible mushroom Pleurotus ostreatus ARC280. Study Design: Laccase activity was assayed by monitoring the product formation rate of enzymatic oxidation of syringaldazine spectrophotometrically at 525 nm. Place and Duration of Study: Department of Microbial Chemistry, Genetic Engineering and Biotechnology Division, National Research Centre, Dokki, Cairo, Egypt, between May 2009 and October 2010. Methodology: Pleurotus ostreatus ARC280 was maintained on potato dextrose agar medium. The liquid medium used for the laccase production by the fungal culture during its growth in submerged fermentation was selected from eight liquid media for inducing laccase production. Parameters such as incubation period, temperature, pH of the production medium, carbon and nitrogen sources and other nutritional parameters were studied using syringaldazine as a model substrate for laccase activity determination. Results: In the present work, Eight media with different components were screened. The enzyme formed by Pl. ostreatus ARC280 was localized mainly in the extra-cellular fraction. Laccase formation reaches its maximum value with specific activity of about 140 U/mg protein at the twenty-sixth day of incubation, pH 5.0 and 28ºC. Among the various wastes used, corn stover induces the highest laccase production with specific activity of 75.48 U/mg protein. Soluble starch at 1.5% (w/v) and ammonium sulfate was found to be the best carbon and nitrogen sources for laccase formation, respectively. The optimal concentrations of Tween-80 and CuSO4. 5H2O, were found to be 0.1% (v/v) and 100μM and cause enzyme induction by about 44% and 19% than control, respectively. Conclusion: Laccase production by Pl. ostreatus ARC280 has been shown to depend markedly on the composition of the culture medium, carbon, nitrogen content and inducer compounds and governed by parameters such as pH of the production medium and other nutrition parameters.
Aim: The study evaluated various fermentation conditions for the production of mannanase. Place and Duration of Study: Industrial Biotechnology Research Laboratory (IBRL), School of Biological Sciences, Universiti Sains Malaysia, 11800 Penang, Malaysia between May 2009 and September 2010. Methodology: Solid substrate fermentation was carried out in a shallow aluminum tray system (16 cm x 16 cm x 5 cm) for maximum mannanase production by Aspergillus niger USM F4 using rice husk as a substrate. Results: The maximum mannanase activity of 119.91 U/g substrate was achieved on the 6 days of cultivation when the optimized physical parameters were used (substrate thickness of 1.6 cm or equivalent to 80 g of 0.75 mm rice husk, moisture content to substrate ratio of 1:1 (w/v), cultivation temperature at room temperature (28±2ºC), inoculum size of 6x106 spores/ml and in static condition (no mixing during the fermentation process). The results showed an increment of about 30.79% of mannanase activity after the optimization (119.91 U/g substrate) compared to before optimization (91.68 U/g substrate). Conclusion: The results obtained from this study revealed that rice husk can be used as a substrate for mannanase production in solid state fermentation process.
This work is aimed to study the optimal conditions of extraction and development of novel purification process for α-Amylase from pericarp of Borassus flabellifer fruit. Optimization was done by Response Surface Methodology (RSM) using Box-Behnken design. The variables chosen for this purpose are pH (X1), temperature (X2, °C) and CaCl2 concentration (X3, ppm). A total of 9 runs were conducted, varying each factor while others were kept constant. The contribution of each factor was established giving raise to significant t-values and p-values. This revealed that the three variables are essential for activity of the enzyme. Based on the obtained optimal conditions from RSM studies, enzyme formation was successfully achieved with an activity of 28.8 U and concentration of 1.4 mg/ml for the 90% ammonium sulfate precipitated dialyzed enzyme sample. A novel affinity chromatographic process was developed for purification process and by this process the enzyme concentration was found to be 0.032mg/ml and activity was determined as 4.76 U.
Aim: Humans and animals interact with their environments on a daily basis and, as a consequence, are exposed to a broad spectrum of synthesized chemicals present in the food they eat, the air they breathe and the water they drink including glyphosate. This study was aimed at investigating the effects of glyphosate on the sperm dynamics of male albino rats and the protective effects of ascorbic acid. Methods: Twenty five mature male albino rats were weighed and divided into five groups in a completely randomized design (CRD). Group 1 rats served as the control. Rats in groups 2 and 4 received 250ml/kg and 500ml/kg of glyphosate while groups 3 and 5 rats were administered with 250ml/kg and 500ml/kg of glyphosate and 200mg/kg of ascorbic acid, respectively, which were administered orally using oral gavages. The treatment regimen lasted for 65 days. Results: Our results showed that there were significant adverse effects (P<0.05) of glyphosate treatment on sperm parameters and the cyto-architecture of the gonad, which showed disruption in the seminiferous tubules, necrotic germinal epithelium and clumped Leydig cells. However, administering the rats with ascorbic acid caused significant ameliorating effects on the parameters investigated. Conclusion: Succinctly, glyphosate exposure to animals is detrimental to their reproductive physiology, including the cellular integrity of the gonads. This not notwithstanding, administering the affected animals with ascorbic acids might reduce the toxicity inflicted by the glyphosate.
Mutation breeding in crop plants is an effective approach in improvement of crop having narrow genetic base such as groundnuts (Arachis hypogaea L.). Determination of effective irradiation dose is prerequisite for mutation breeding and development of genetic variability by induced mutation. Three groundnuts (Arachis hypogaea L.) genotypes (JL12, JL24 and Kimpese) were irradiated to the absorbed doses of 100, 200, 400 and 600 Gy for effective dose determination and to compare their sensitivity to different doses of gamma irradiation in a completely random design. It was found that, irradiation reduced significantly germination and survival percentages of seedlings in higher doses and this reduction was more pronounced in JL 24 cultivar. This sensitivity expresses himself distinctly to the rank of stem lengths and roots. Results show a negative interrelationship indeed between doses of irradiation applied and lengths of stems and roots. With attention to LD50 data, our results indicated that optimum doses were 200 Gy for JL12 and Kimpese, and 100 Gy for JL24. We concluded that JL24 are more sensitive to gamma irradiation than JL12 and Kimpese.