Immobilization of Aspergillus oryzae tyrosine hydroxylase on ZnO nanocrystals for improved stability and catalytic efficiency towards L-dopa production.

The current study focuses on the submerged fermentation of tyrosine hydroxylase (TH) from Aspergillus oryzae IIB-9 and its immobilization on zinc oxide nanocrystals (ZnO-NPs) for increased L-dopa production. The volume of Vogel's medium (75 ml), period of incubation (72 h), initial pH (5.5), and size of inoculum (1.5 ml) were optimal for maximum TH activity. The watch glass-dried (WG) and filter paper-dried (FP) ZnO-NPs were prepared and characterized using analytical techniques. The UV-Vis spectra revealed 295 and 285 nm absorption peaks for WG-ZnO-NPs and FP-ZnO-NPs dispersed in isopropanol. X-ray diffraction analysis confirmed the crystalline nature of ZnO-NPs. FTIR spectra band from 740 to 648.1/cm and 735.8/cm to 650.1/cm showed the stretching vibrations of WG-ZnO-NPs and FP-ZnO-NPs, respectively. The particle size of ZnO-NPs observed by scanning electron microscopy (SEM) images was between 130 and 170 nm. Furthermore, the stability of immobilized TH on ZnO-NPs was determined by varying the incubation period (10 min for WG-NPs and 15 min for FP-NPs) and temperature (45 °C and 30 °C for WG and FP-NPs, respectively). Incubating enzymes with various copper, iron, manganese, and zinc salts studied the catalytic efficiency of TH. Immobilization of TH on ZnO-NPs resulted in an 11.05-fold increase in TH activity, thus enhancing stability and catalytic efficiency.

Effect of Chilled Storage on Antioxidant Capacities and Volatile Flavors of Synbiotic Yogurt Made with Probiotic Yeast Saccharomyces boulardii CNCM I-745 in Combination with Inulin.

Fermentation of available sugars in milk by yogurt starter culture initially and later by Saccharomyces boulardii (Probiotic yeast) improves the bioavailability of nutrients and produces bioactive substances and volatile compounds that enhance consumer acceptability. The combination of S. boulardii, a unique species of probiotic yeast, and inulin, an exopolysaccharide used as a prebiotic, showed remarkable probiotic and hydrocolloid properties in dairy products. The present study was designed to study the effect of fermentation and storage on antioxidant and volatile capacities of probiotic and synbiotic yogurt by incorporation of S. boulardii and inulin at 1%, 1.5%, and 2% (w/v), compared with the probiotic and control plain yogurt. All samples were stored at 4 °C, and during these four weeks, they were analyzed in terms of their antioxidant and volatile compounds. The synbiotic yogurt samples having inulin and S. boulardii displayed significantly higher DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical activity values and more values of TPC (total phenol contents) than control plain yogurt. A total of 16 volatile compounds were identified in S5-syn2 and S4-syn1.5, while S3-syn1 and S2-P had 14, compared with the control S1-C plain yogurt samples, which had only 6. The number of volatile compounds increased with the increasing concentration of inulin throughout the storage period. Therefore, this novel synbiotic yogurt with higher antioxidant and volatile compounds, even with chilling storage conditions, will be a good choice for consumer acceptability.

Novel Ergot Alkaloids Production from Penicillium citrinum Employing Response Surface Methodology Technique.

Ergot alkaloids are novel pharmaceutical and therapeutic agents synthesized in this study using fungal species Penicillium citrinum. To get the maximum yield of ergot alkaloids a statistical process of response surface methodology was employed using surface culture fermentation technique. Initially, the strain of Penicillium was improved using physical (ultraviolet (UV) and chemical (ethyl methane sulfonate (EMS) treatments to get the maximum yield of ergot alkaloids through surface culture fermentation technique. After improving the strain, survival rate of colonies of Penicillium citrinum treated with UV and EMS was observed. Only 2.04% living colonies were observed after 150 min of exposure of Penicillium citrinum in UV light and 3.2% living colonies were observed after 20 min of the exposure in EMS. The mutated strains of Penicillium citrinum were screened for their production of ergot alkaloids and after fermentation experiments, maximum yield was obtained from PCUV-4 and PCEMS-1 strains. After strain improvement, Plackett-Burman design (PBD) and Box-Behnken design (BBD) of RSM were employed and 10-fold yield enhancement (35.60 mg/100 mL) of ergot alkaloids was achieved. This enhancement in yield of ergot alkaloids proved the positive impacts of RSM and UV on the yield of ergot alkaloids. The study provides a cost effective, economical and sustainable process to produce medically important ergot alkaloids which can be used in various pharmaceutical formulations to treat human diseases.

Production of nitrogen fixing Azotobacter (SR-4) and phosphorus solubilizing Aspergillus niger and their evaluation on Lagenaria siceraria and Abelmoschus esculentus.

AIMS: Current study was aimed to produce nitrogen fixing Azotobacter sp. (SR-4) and phosphorus solubilizers Aspergillus niger (A. niger) and to evaluate their efficiency as biofertilizers for agricultural practices. METHODS: Two biofertilizer including nitrogen fixing and phosphorus solubilizing were grown. The nitrogen fixing efficiency of Azotobacter (SR-4) was determined by Kjeldahl method. Similarly, Vanadomoybdate method was used to measure the soluble phosphorus while Heinonen method was used to analyze concentration of phytase and phosphatase in the cultures. Furthermore, both biofertilizers were tested in a field trail on Lagenaria siceraria (bottle gourd) and Abelmoschus esculentus (okra). RESULTS: The Azotobacter (SR-4) strain was found efficient nitrogen fixer as 35.08 mg of nitrogen per gram of carbon was produced after 72 h of fermentation. Similarly, A. niger strain excrete extracellular phosphate solubilizing enzymes such as phytase (133UI in 48 h of fermentation) and phosphatase (170UI in 48 h of fermentation) which can solubilize the rock phosphate and make it available to plants. In field trials on selected plants (L. siceraria and A. esculentus), both biofertilizers showed significant increase in plant height, leaf length/width, fruit size and number of fruits per plant when compared with controls/untreated plants. Furthermore, plants co-inoculated with both the N fixing Azotobacter and phosphorus solubilizing A. niger have enhanced performance than those treated with each biofertilizer alone. CONCLUSION: The inoculation of seeds with A. niger and Azotobacter may replace costly and environment toxic chemical fertilizers with environment friendly and cost effective biofertilizers.

Production of recombinant human epidermal growth factor in Pichia pastoris

Abstract This study was carried out to express human epidermal growth factor (hEGF) in Pichia pastoris GS115. For this aim, the hEGF gene was cloned into the pPIC9K expression vector, and then integrated into P. pastoris by electroporation. ELISA-based assay showed that the amount of hEGF secreted into the medium can be affected by the fermentation conditions especially by culture medium, pH and temperature. The best medium for the optimal hEGF production was BMMY buffered at a pH range of 6.0 and 7.0. The highest amount of hEGF with an average yield of 2.27 µg/mL was obtained through an induction of the culture with 0.5% (v/v) methanol for 60 h. The artificial neural network (ANN) analysis revealed that changes in both pH and temperature significantly affected the hEGF production with the pH change had slightly higher impact on hEGF production than variations in the temperature.

Production of recombinant human epidermal growth factor in Pichia pastoris.

This study was carried out to express human epidermal growth factor (hEGF) in Pichia pastoris GS115. For this aim, the hEGF gene was cloned into the pPIC9K expression vector, and then integrated into P. pastoris by electroporation. ELISA-based assay showed that the amount of hEGF secreted into the medium can be affected by the fermentation conditions especially by culture medium, pH and temperature. The best medium for the optimal hEGF production was BMMY buffered at a pH range of 6.0 and 7.0. The highest amount of hEGF with an average yield of 2.27µg/mL was obtained through an induction of the culture with 0.5% (v/v) methanol for 60h. The artificial neural network (ANN) analysis revealed that changes in both pH and temperature significantly affected the hEGF production with the pH change had slightly higher impact on hEGF production than variations in the temperature.

Effect of alkaline pretreatment on delignification of wheat straw.

This study was conducted to analyse structural changes through scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) after alkaline pretreatment of wheat straw for optimum steaming period. During the study, 2 mm size of substrate was soaked in 2.5% NaOH for 1 h at room temperature and then autoclaved at 121°C for various steaming time (30, 60, 90 and 120 min). Results revealed that residence time of 90 min at 121°C has strong effect on substrate, achieving a maximum cellulose content of 83%, delignification of 81% and hemicellulose content of 10.5%. Further SEM and FTIR spectroscopy confirmed structural modification caused by alkaline pretreatment in substrate. Maximum saccharification yield of 52.93% was achieved with 0.5% enzyme concentration using 2.5% substrate concentration for 8 h of incubation at 50°C. This result indicates that the above-mentioned pretreatment conditions create accessible areas for enzymatic hydrolysis.

Comparison of the estimation capabilities of response surface methodology and artificial neural network for the optimization of recombinant lipase production by E. coli BL21.

Response surface methodology (RSM) and artificial neural network (ANN) were used to optimize the effect of four independent variables, viz. glucose, sodium chloride (NaCl), temperature and induction time, on lipase production by a recombinant Escherichia coli BL21. The optimization and prediction capabilities of RSM and ANN were then compared. RSM predicted the dependent variable with a good coefficient of correlation determination (R² and adjusted R² values for the model. Although the R (2) value showed a good fit, absolute average deviation (AAD) and root mean square error (RMSE) values did not support the accuracy of the model and this was due to the inferiority in predicting the values towards the edges of the design points. On the other hand, ANN-predicted values were closer to the observed values with better R², adjusted R², AAD and RMSE values and this was due to the capability of predicting the values throughout the selected range of the design points. Similar to RSM, ANN could also be used to rank the effect of variables. However, ANN could not predict the interactive effect between the variables as performed by RSM. The optimum levels for glucose, NaCl, temperature and induction time predicted by RSM are 32 g/L, 5 g/L, 32°C and 2.12 h, and those by ANN are 25 g/L, 3 g/L, 30°C and 2 h, respectively. The ANN-predicted optimal levels gave higher lipase activity (55.8 IU/mL) as compared to RSM-predicted levels (50.2 IU/mL) and the predicted lipase activity was also closer to the observed data at these levels, suggesting that ANN is a better optimization method than RSM for lipase production by the recombinant strain.