Alkaline Protease Production from 6BS15-4 Using Dairy Effluent and Its Characterization as a Laundry Detergent Additive.

Protease is a widely used enzyme particularly in the detergent industry. In this research, we aimed to isolate alkaline protease-producing bacteria for characterization as a laundry detergent additive. The screening of alkaline protease production was investigated on basal medium agar plus 1% skim milk at pH 11, with incubation at 30°C. The highest alkaline protease-producing bacterium was 6BS15-4 strain, identified as by 16S rRNA gene sequencing. While the optimum pH was 12.0, the strain was stable at pH range 7.0-12.0 when incubated at 45°C for 60 min. The alkaline protease produced by 6BS15-4 using dairy effluent was characterized. The optimum temperature was 60°C and the enzyme was stable at 55°C when incubated at pH 11.0 for 60 min. Metal ions K, Mg, Cu, Na, and Zn exhibited a slightly stimulatory effect on enzyme activity. The enzyme retained over 80% of its activity in the presence of Ca, Ba, and Mn. Thiol reagent and ethylenediaminetetraacetic acid did not inhibit the enzyme activity, whereas phenylmethylsulfonyl fluoride significantly inhibited the protease activity. The alkaline protease from 6BS15-4 demonstrated efficiency in blood stain removal and could therefore be used as a detergent additive, with potential for various other industrial applications.