Currently the development of green chemistry approach with the use of biomaterial-based activities of microbial cells in the synthesis of various nanostructures has attracted a great attention. In this study, we report on the use of bacterium, Bacillus cereus as a biotemplating agent for the formation of zinc oxide nanoparticles with raspberry- and plate-like structures through a simple thermal decomposition of zinc acetate by maintaining the original pH of the reaction mixtures. Possible mechanism on the formation of the nanostructures is proposed based on the surface chemistry and biochemistry processes involved organic-inorganic interactions between zinc oxide and the microbial cells.
Enzymatic production of bioxylitol from lignocellulosic biomass (LCB) provides a promising alternative to both chemical and fermentative routes. This study aimed to assess the impacts of catalytic variables on bioxylitol production from wood sawdust using xylose reductase (XR) enzyme and to optimize the bioprocess. Enzyme-based xylitol production was carried out in batch cultivation under various experimental conditions to obtain maximum xylitol yield and productivity. The response surface methodology (RSM) was followed to fine-tune the most significant variables such as reaction time, temperature, and pH, which influence the synthesis of bioxylitol from sawdust hydrolysate and to optimize them. The optimum time, temperature, and pH became were 12.25 h, 35 °C, and 6.5, respectively, with initial xylose 18.8 g/L, NADPH 2.83 g/L, XR 0.027 U/mg, and agitation 100 rpm. The maximum xylitol production was attained at 16.28 g/L with a yield and productivity of 86.6% (w/w) and 1.33 g/L·h, respectively. Optimization of catalytic parameters using sequential strategies resulted in 1.55-fold improvement in overall xylitol production. This study explores a novel strategy for using sawdust hemicellulose in bioxylitol production by enzyme technology.
The use of nanominerals, such as nano-zinc, represents a promising and emerging technology in the animal farming industry. Due to the small particle size and bioavailability of nano-zinc, it can be easily assimilated in the digestive system, thereby reducing excretion and environmental pollution. The present study was conducted to assess the effects of zinc oxide nanoparticles (ZnONPs) on the growth performance, zinc (Zn) concentration in edible tissues, thiobarbituric acid reactive substance, and corticosterone concentrations in broilers reared under normal or heat stress environmental conditions. The experiment was performed with a completely randomized design based on a 4 × 2 factorial arrangement consisting of 4 diets (basal diet + 60 mg/kg conventional zinc oxide as control diet; basal diet + 40 mg/kg of ZnONPs; basal diet + 60 mg/kg of ZnONPs; and basal diet + 100 mg/kg of ZnONPs) and 2 environmental conditions (normal and heat stress). On day 22, birds from each dietary group were divided equally to normal temperature (23 ± 1°C throughout) or heat stress conditions (34 ± 1°C daily for 6 h from 10:00 am until 4:00 pm). From 1 to 42 D of age, the broiler chickens fed 100 mg/kg ZnONPs exhibited lower feed intake and feed conversion ratio than the control. The accumulation of Zn in the liver of broilers was significantly higher among all treatment groups compared to breast and thigh muscle tissues regardless of the temperature conditions. At 40 and 60 mg/kg ZnONPs, the malondialdehyde content increased in thigh muscle of broilers at 7 D postmortem, indicating that ZnONPs potentially inhibited the antioxidant system in muscle tissues. The control and ZnONPs at 40 mg/kg and 60 mg/kg led to low serum corticosterone levels that may be attributed to the antioxidant and antistress properties of Zn. Taken together, although supplementation with ZnONPs at 40 mg/kg and 60 mg/kg alleviated the negative results of heat stress, further research is needed to determine the optimal level of dietary ZnONPs supplementation.
Zinc oxide nanoparticles (ZnONPs) exhibit abundant biomedical applications. Anisotropic ZnONPs with a defined shape and size were synthesized using Bacillus megaterium (NCIM 2326) cell free extract as a bio-reductant. The study investigated the multidimensional effect of ZnONPs on Helicobacter pylori strains and assessed its biosafety in normal human mesenchymal stem cells (hMSc). The highly stable ZnONPs were produced using B. megaterium and Zinc nitrate as a precursor. The phase of ZnONPs formation and structural characterization were performed by UV- visible (UV-Vis), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and Field Emission Scanning electron microscopy (FESEM) analysis. Furthermore, the ZnONPs exhibited higher biocompatibility against human mesenchymal stem cells (hMSC) and proved to be potentially safe in mammalian cells. Corroborating the current investigation, we described the anti-H. Pylori dosage of ZnONPs was safe to hMSC and could efficiently use as nano-antibiotic.