Today, the overall occurrence of re-emerging and rising illnesses has been a serious load on economies as well as public health. Here, we describe a simple, nontoxic and eco-friendly method for the synthesis of milk protein (MP)-stabilized silver nanoparticles (MP-s-AgNPs) using ultrahigh-temperature full cream milk. Highly stable AgNPs were prepared with a fair control over their size, without using any reducing or stabilizing agent, and their formation was attributed to the presence of the MP casein. Ag+ ion reduction was possibly caused by the MPs. The synthesized MP-s-AgNPs were characterized in detail by ultraviolet-visible spectroscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, transmission electron microscopy and dynamic light scattering. MP-s-AgNPs showed inhibitory activity against both Gram-positive (Bacillus subtilis and Staphylococcus aureus) and Gram-negative microorganisms (Salmonella typhi and Escherichia coli). Moreover, MP-s-AgNPs were found to be more toxic to bacteria than to fungi (Aspergillus fumigatus, Aspergillus ochraceus and Penicillium chrysogenum).

Second-generation biofuels, fuels produced from lignocellulosic materials, including wood, agricultural residues and biomass waste include bioethanol, biodiesel and biogas. These fuel sources have great potential as useful substitutes to conventional fossil fuels. Biomass sources are also non-toxic and biodegradable energy sources that can be produced from a wide range of organic materials resulting in economic and renewable energy source. Pretreatment of lingocellulosic biomass is required to reduce physicochemical restrictions that hinder the accessibility of sugars necessary for hydrolysis and fermentation. Various pretreatment processes exist, but all of them produce inhibitory compounds that ultimately reduce ethanol production and cell viability of the fermenting microorganism, Saccharomyces cerevisiae. In this study different combinations of inhibitors (acetic acid, formic acid and vanillin) were considered to mimic realistic fermentation conditions during bioethanol production; ethanol yield and cell viability were then concurrently measured over a period of 48 h. The combination of acetic acid and formic acid exhibited ethanol reduction up to 11 ± 3.74%, while cell viability decreased by 23 ± 6.61%. Acetic acid and vanillin reduced ethanol production by 25 ± 1.77% and cell viability by 4 ± 4.38%. Formic acid and vanillin inhibited ethanol production by 31 ± 3.14% and cell viability 16 ± 7.54%. Finally, the synergistic effect of all three inhibitors reduced the final ethanol production by 58 ± 5.09% and cell viability by 27 ± 5.44%, indicating the toxic effect of the synergistic combination.

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In this study various coagulants and flocculants were tested for optimum removal of COD from brewery wastewater. The coagulants used were ferric chloride and an organic coagulant mixture obtained from the brewery company. The flocculants used were a cationic flocculant (Genesys' genefloc, polyquaternary amine), an anionic flocculant (Senfloc 5210), a non-ionic flocculant (Senfloc 5330) and a cationic acrylamide copolymer in aqueous dispersion (Brewery flocculant) for comparison. The organic coagulant mixture in aqueous solution was more effective than the ferric chloride at the same optimal dosage of 25 ppm. The ferric chloride and organic coagulant mixture used alone achieved COD removal efficiencies of 32.7% and 48.5% at a pH of 5.65 respectively while their performances for turbidity removal at pH 5.65 were 63.3% and 91.9% respectively. The best results were achieved when using the ferric chloride in combination with the cationic acrylamide copolymer in aqueous dispersion (Brewery flocculant) at an optimum dosage of 30 ppm and when using the organic coagulant mixture in aqueous solution in combination with the cationic acrylamide copolymer in aqueous dispersion (Brewery flocculant) at an optimum dosage of 10 ppm. When using ferric chloride in combination with the cationic acrylamide copolymer in aqueous dispersion (Brewery flocculant) and the organic coagulant mixture in aqueous solution in combination with the cationic acrylamide copolymer in aqueous dispersion (Brewery flocculant), COD removal efficiencies of 79.6% and 78.2% at a pH of 5.85 respectively was achieved, while they exhibited similar performance for turbidity removal at pH 5.85 of 99.7%. The optimization tests carried out in this study have allowed to improve the understanding of turbidity and COD removal mechanisms and achieved lower dosages of coagulants and flocculants for better treatment, therefore suggesting a more economical approach. Comparing the achieved results with the standard disposal values, it can be seen that the results gathered in