Zinc Oxide Nanoparticles (ZnONPs) are one of the most widely used metal oxide nanoparticles in biological applications because of their outstanding biocompatibility, affordability, and low toxicity. In biomedicine, ZnONPs have shown promise, particularly in the disciplines of anticancer and antibacterial fields. In comparison to other standard synthesis methods, the environmentally-friendly synthesis of metallic nanoparticles utilizing various plant extracts is a good option. The current research focuses on the synthesis of zinc oxide nanoparticles (ZnONPs) from R. sativus leaf extract under various physical conditions (Precipitation method). Analytical methods were used to confirm and characterize the produced ZnONPs. The spherical nature of the produced nanoparticles was established by SEM analysis. The generation of very pure ZnONPs was confirmed by EDS data. The crystalline nature of the produced nanoparticles, with a particle size of 66.47 nm, was confirmed by XRD. The XRD graphs’ presence of the (100), (002), and (101) planes strongly suggest the production of wurtzite ZnO. The visual and infrared area exhibits transmissions of 84 percent in the pH 10 nanoparticles. The band gap of the nanoparticles increases from 3.34 to 3.38 eV when the pH increases. These nanoparticles were effective against both Gram-positive and Gram-negative bacteria. The effect of several process parameters such as pH and temperature were investigated, and the best conditions were discovered to be pH 12 and 80 °C, respectively. The effect of ZnONPs was tested with human breast cancer cells (MCF-7), and they showed significant cytotoxic results. Collectively, our data suggest that ZnONPs of R. sativus leaf extract inhibit breast cancer cell lines. The ZnONPs are, therefore, a prospective source of chemopreventive drugs that merit additional exploration in order to uncover lead compounds with cancer chemotherapeutic potential.

Pectinolytic enzymes are related enzymes that hydrolyze pectic substances. Pectinolytic enzymes are of great interest in industrial applications for softening fruits, extracting and clarifying juices, extracting olive oil, retting textile fibers, preparing gel, and isolating protoplasts. The current work presents acidic extracellular pectinase production using low-cost agro-industrial waste with the indigenously isolated novel strain Aspergillus cervinus. Two fungal isolates, ARS2 and ARS8, with maximum pectinase activity, 41.88 ± 1.57 IU/mL and 39.27 ± 1.14 IU/mL, respectively, were screened out of 27 isolates from decayed fruit peels (orange, banana, and lemon) and soil containing decomposed vegetables. The isolate ARS2, identified as Aspergillus cervinus by molecular characterization, showed the highest pectinase activity of 43.05 ± 1.38IU/mL during screening and was further used for media component screening and optimization studies. To understand their effect on pectinase activity, one-factor-at-a-time (OFAT) studies were conducted on carbon sources, nitrogen sources, and mineral salts. The OFAT results showed the highest pectinase activity for orange peel (carbon source) at 44.51 ± 1.33 IU/mL, peptone (nitrogen source) at 45.05 ± 1.04 IU/mL, and NaH₂PO₄ (mineral salts) at 43.21 ± 1.12 IU/mL. The most significant media components screened by the Plackett–Burman (PB) design based on the p-value, Pareto chart, and main effect plot, were orange peel (p < 0.001), peptone (p < 0.001), NaH₂PO₄ (p < 0.001), and KH₂PO₄ (p < 0.001), which were further optimized using Response Surface Methodology (RSM) and Central Composite Design (CCD). The optimization results for the media components showed a maximum pectinase activity of 105.65 ± 0.31 IU/mL for 10.63 g orange peel, 3.96 g/L peptone, 2.07 g/L KH₂PO₄, and 2.10 g/L NaH₂PO₄. Thus, it was discovered that the indigenously isolated novel strain Aspergillus cervinus ARS2 was able to successfully produce a significant amount of pectinase using agro-industrial waste. Therefore, it can be considered for the large-scale optimized production of pectinase to meet industrial demands.

The demand for microbial pectinase has increased due to its vast applications in different industries. The current study dealt with the synthesis of pectinase by a novel native strain Aspergillus cervinus ARS2 using agro-industrial waste. Comparative studies conducted on pectinase production by submerged fermentation (SmF) and solid-state fermentation (SSF) showed that pectinase activity was more increased in SSF (44.51 ± 1.33 IU/mL) than in SmF (40.60 ± 1.15 IU/mL) when using orange peel as a substrate. Using SSF, one-factor-at-a-time (OFAT) studies were conducted, considering different process variables such as inoculum size, initial pH, incubation time, moisture content, incubation temperature, and substrate particle size, all of which affected the pectinase activity. OFAT results showed the highest pectinase activity at an inoculum size of 10⁶ spores/mL (43.11 ± 1.06 U/mL), an incubation time of 6 days (43.81 ± 1.21 U/mL), a moisture content of 100% (44.30 ± 1.69 U/mL), a substrate particle size of 1.7 mm (42.06 ± 1.20 U/mL), an incubation temperature of 37 °C (45.90 ± 1.33 U/mL), and an initial pH of 4 (43.31 ± 0.89 U/mL). The identified significant process variables were then optimized by response surface methodology (RSM)-central composite design (CCD). The results showed optimum pectinase activity of 107.14 ± 0.71 IU/mL for a substrate particle size of 2 mm, an incubation temperature of 31.5 °C, an initial pH of 4.9, and a moisture content of 107%, which was obtained from the Minitab optimizer. By using statistical optimization, the pectinase production from the isolated novel fungal strain A. cervinus ARS2 was increased 2.38-fold. Therefore, the A. cervinus ARS2 strain can be further explored for large-scale pectinase production which could meet the growing industrial demands.

Silver nanoparticles (Ag-NPs) have attracted huge importance due to their distinctive chemical, biological and physical properties. Silver nanoparticles are widely synthesized by the chemical method, which involves the use of toxic chemicals which affects its applications. The bio-reduction method, in comparison with chemical method is more economic and eco-friendly. In the present work, the bio-based production of Ag-NPs was done by using peel extract of orange (citrus sinensis), which played a role of reducing and stabilizing agent. The biosynthesis of silver nanoparticles was optimized by one factor at a time (OFAT) with respect to peel extract concentration, silver nitrate concentration and reaction temperature. The green synthesized silver nanoparticles were characterized by UV-visible spectroscopy, Fourier transforms infrared (FT-IR) spectroscopy, Scanning electron microscopy (SEM) and X-ray diffraction (XRD). Disk diffusion method was used for the study of antibacterial activity of the bio-synthesized silver nanoparticles against the bacteria Escherichia coli and Staphylococcus aureus. The results showed that at a peel extract concentration of 6%, the temperature of 60oC and silver nitrate concentration of 0.1M, the synthesis of Ag-NPs was effective. The orange peel synthesized Ag-NPs showed effective antibacterial activity against both bacteria. However better activity was observed against bacterium Staphylococcus aureus. The results confirmed the synthesis of Ag-NPs using peel extract of citrus sinensis and its role as antibacterial agent.

Xylanase is an enzyme that acts on xylan and degrades it into xylose. Xylanase may be produced by several different microbes such as bacteria and fungi. Xylanase has significant applications in food industries for improving dough handling and improving the quality of baked products in the extraction of starch, coffee, and plant oils. Xylanase, along with pectinase and cellulose, has enormous application in the clarification of fruit juices. In the present study, xylanase was produced by solid-state fermentation using lemon peel as substrates. Aspergillus Niger was induced to produce xylanase by frequent sub-culturing on a medium containing 2% xylan. OFAT was analyzed by using several fermentation parameters such as moisture content, particle size, incubation period, incubation temperature, peptone concentration, and pH of the extraction buffer. Under optimized conditions, the maximum xylanase activity was found for particle size of 1.7mm, moisture content of 80%, peptone concentration in nutrient solution at 0.3%, and extraction pH of 7.0. Hence, xylanase can be further subjected to down streaming processes and therefore for various applications.