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The primary goal of this study is to convert waste cooking oil into biodiesel using immobilized lipase enzyme from Bacillus halotolerans. The used cooking oil acid quantity is 3.95 mg KOH/g. In the optimal settings of enzymatic transesterification, methanol:oil ratio 6:1, reaction time 120 min, lipase enzyme concentration 0.6 mg/ml, and temperature 32 °C, the biodiesel yield was 29.64 mg/kg. ANOVA analysis revealed that enzyme concentration and methanol:oil ratios are the two most dominating factors affecting biodiesel yield. The high R2 99.87 and R2 adj 99.56 values indicate that the fitted model agrees with the predicted biodiesel and actual experimental values. Bio-supported beads could preserve up to 76.62 percent of original activity after six cycles of immobilized lipase enzyme reusability testing. Furthermore, the characteristics of biodiesel were assessed and confirmed using the glycerol assay method and FTIR analysis. The proposed technique has the potential to reduce biodiesel production costs and make waste cooking oil disposal easier. Additionally, this study found that the optimization process improves and enhances the process of converting waste cooking oil to biodiesel.

Cellulase was produced by Cellulomonas uda utilizing banana stem waste by solid state fermentation (SSF). The different parameters effects considered like particle size of substrate, pH(incubation and extraction), incubation period, temperature (incubation and extraction), media components (yeast extract and peptone) and moisture of substrate on the production of cellulase was investigated. The optimum activity of cellulase produced by Cellulomonas uda on banana waste for particle size (6.97 IU/min for 1mm), extraction pH (7.13 IU/min for pH 7), incubation pH(6.97 IU/min for pH 7), extraction temperature (7.10 IU/min for 500C), incubation temperature (7.20 IU/min for 450C), incubation period (7.20 IU/min on 3rd day), moisture content (7.12 IU/min for 100% ), peptone content ( 7.23 IU/min for 0.5 gm) and yeast extract content (7.18 IU/min for 0.30gm) was recorded. The cellulase produced by Cellulomonas uda by using banana stem waste indicates the socio-econic utilization of agricultural waste. After purification and characterization; cellulase enzyme can be used in industrial processes.

Xylanases are enzymes that convert xylan into xylose, xylobiose, and xylotriose. The present study deals with the production and optimization of xylanase through Solid-State Fermentation (SSF) using different agricultural wastes by Aspergillus spp. The Plackett Burman (PB) design was used to screen significant media components affecting the xylanase production. The carbon sources screened were wheat bran, rice bran, sugarcane bagasse, corn cob, and orange peel. The nitrogen sources screened were yeast extract, peptone, (NH4)2SO4, Na2NO3, and urea. Also, nine different salts such as KCl, MgSO4, Na2HPO4, CaCl2, FeSO4, ZnSO4, Na2CO3, KH2PO4, and NaH2PO4 which act as trace elements were screened. The results showed that wheat bran, yeast extract, Na2NO3 and KCl are the significant factors that affect xylanase production. A 33 Full Factorial Design (FFD) was performed to optimize the significant media components (wheat bran, KCl, yeast extract) obtained from PB design using Response Surface Methodology (RSM). Statistical analysis of results showed that wheat bran, KCl, yeast extract, and interaction between wheat bran and yeast extract were found to be significant. The optimum concentration of wheat bran, KCl, yeast extract was 8 g/L, 0.1 g/L and 3 g/L. The Partial purification of xylanase was carried out using ammonium salt precipitation and dialysis. Gel filtration chromatography was performed to optimize the elution time, which was found to be 6 minutes. Application of xylanase in orange juice clarification was studied at 40 °C, 50 °C, and 60 °C. The optimum temperature obtained was 60 ºC.

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.

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.

Feathers, rich in keratin, are usually the unused by-products of poultry industries. In addition, the cast-off X-ray films serve as secondary sources of silver, and the traditional method of silver extraction from this source is costly and not eco-friendly. Therefore, the current study focuses on protease production using a freshwater bacterium Chryseobacterium cucumeris SARJS-2, aiming to convert these wastes into useful products. The protease production was optimized by one-factor-at-a-time (OFAT), followed by Plackett Burman design (PBD) and response surface methodology (RSM). The protease production got enhanced by more than two folds after the statistical optimisation. Upon partial purification, the enzyme activity increased by approximately three folds. The protease was active in the range of temperatures from 25 to 75 °C, but the optimum temperature was recorded as 35 °C. The protease exhibited detergent compatibility and organic solvent stability. The detergent compatibility suggests the protease could be a detergent additive. It was also found that the presence of Fe(+2) enhanced protease activity. The protease was tested for stain removal, feather degradation and silver recovery applications. It was found that the protease could efficiently remove stains of blood and tomato sauce. In addition, the protease was found to be a successful candidate for feather degradation, thereby feather-hydrolysate production which has prominent roles as nature-friendly fertilizer and animal feed ingredient. The protease also degraded gelatin from the X-ray films to release the silver-halides for silver recovery. The results recommend that the SARJS-2 protease is a potential candidate for use in eco-friendly applications in various industrial sectors.

The present research work emphasis on immobilization of lipase on PVA-alginate beads, which are used for biodiesel production via transesterification. The optimization of temperature, pH, and reusability of was performed on PVA-Alginate beads. The highest enzyme activity was found at a temperature of 40°C and pH 4.00. After six consecutive cycles of using the immobilized enzyme, the residual activity was 60% of the initial activity. The immobilized beads were stored at 4°C without buffer after 6 weeks, the immobilized enzyme retained 76.62% of initial activity.. The second-order mathematical model was developed using RSM. Transesterification process parameters were optimized by using ‘Full Factorial Design’ (FFD) with free lipase and immobilized lipase. The different factors considered for optimization were methanol/oil (M/O) ratio, reaction time, the weight of the catalyst with constant temperature and agitation speed. FFD was performed for free lipase, obtained the highest yield with optimum conditions; M/O ratio 9:1, reaction time 90 minutes, and weight of the catalyst was 0.3gm. Similarly, FFD was performed with immobilized lipase with the highest yield at 6:1 M/O ratio, 3 hours reaction time, the weight of the catalyst 3gm. FTIR was performed for the PVA-Alginate beads and lipase immobilized PVA-Alginate beads From FTIR spectra, the peaks shift from 1746 cm -1 to 1742 cm -1 signified the formation of biodiesel.