In leather industries and tanneries, large amount of wastes has been disposed; which polluting water, soil, and atmosphere and causing serious human health problems. In particular, chemical dehairing process of leather industries produces fair amount of toxic wastes. It is, thus, urgently needed to use alternative processes free from pollution. As more than 90% of keratin is contained in feather, it is desirable to develop bioremediation process using keratinolytic microorganisms. In the present investigation, therefore, we first identified Bacillus cereus and Pseudomonas sp. to be able to produce keratinase. Then, the optimization was performed to maximize the keratinase activity with respect to cultivation temperature, pH, and incubation time. Moreover, the effects of metal ions and various substrates on keratinase activity were also investigated. The result indicates that keratinase activity became maximum at 50°C for both strains, whereas the optimal pH was 10.0 for B. cereus and 7.0 for Pseudomonas sp. The highest keratinase activity of 74.66 ± 1.52 U/mL was attained by B. cereus, whereas 57.66 ± 2.52 U/mL was attained by Pseudomonas sp. Enzymatic dehairing efficiency of leathers was also compared with chemical dehairing (Na2S and CaO), where complete dehairing was achieved by treating them with crude keratinase. Partial enzyme purification was performed by acetone precipitation. Batch cultivation of B. cereus using 1 L fermentor indicates a potential candidate for large-scale keratinase production. Thus, keratinase enzyme by degrading poultry wastes (feather) can be an alternative approach to chemical dehairing in leather industries, thus preventing environmental pollution through bioremediation.

Water turbidity is not a direct indicator of health risk; however, turbidity can provide food and shelter for pathogens as well as promote their re-growth in a distribution system and can interfere with the detection of bacteria and viruses in drinking water. In this study, moringa seed powder, ultra-K ® powder, FS ® powder and scallop powder were used individually or in combination to examine their antibacterial and coagulation properties in pond water. In addition to this treatment, attempts were also taken to convert treated water to drinking water through a 3 step natural bio-sand filtration process. This method would be very useful for areas of Bangladesh with scarcity of drinking water or areas prone to flooding. Results showed that Moringa seed powder alone has strong coagulant and antimicrobial effect at low doses. On the other hand, 0.01% scallop powder has strong antimicrobial activity under typical environmental conditions. However, combination of these two powders showed effective coagulating and antimicrobial capacity to reduce the turbidity and inactivate the number of inherent microorganisms respectively, including coliform and E. coli within 5 min. Similar experimental findings were observed when the mixture of Moringa seed powder and sodium hypochlorite was used. On the other hand, both the commercial ultra-K and FS powder showed strong coagulant and antimicrobial effect within 1 min of application. When this treated water passed through natural bio-sand filtration (charcoal, stone and sand), the resulting water became potable. This small scale work was done in the laboratory and there is a need to scale-up this method to ascertain the reproducibility of the results. The present study suggests that Moringa seed powder and scallop powder are naturally available, cost-effective, and nontoxic antimicrobial agents that have potentials to convert pond water to drinkable water.