Compositions and methods for treating contaminated water
A recombinant Moringa oleifera coagulant protein (MO) produced and secreted by Bacillus has coagulation/flocculation activity. The MO protein and the Bacillus host cells expressing the MO protein can be used in compositions and methods for treating contaminated water, such as drinking water or waste water. The MO protein can coagulate or flocculate suspended solid impurities in the water, which can then be removed.
1. A method for treating contaminated drinking water, comprising contacting the water with an effective amount of a composition, said composition comprising:
a recombinant Moringa oleifera MO protein produced and secreted by Bacillus and having coagulation or flocculation activity,
wherein said MO protein produced and secreted by Bacillus is fused or linked to a Bacillus signal peptide (SP), and wherein;
said signal peptide (SP is at least one selected from the group consisting of: YngK (SEQ ID NO: 5), YxiT (SEQ ID NO: 6), PhrG (SEQ ID NO: 7), YklxW (SEQ ID NO: 8), YycP (SEQ ID NO: 9), YqxI (SEQ ID NO: 10), YkwD (SEQ ID NO: 11), YraJ (SEQ ID NO: 12), AspB (SEQ ID NO: 13), YybN (SEQ ID NO: 14), AprE (SEQ ID NO: 15), YjdB (SEQ ID NO: 16), YxaK (SEQ ID NO: 17), and YusW (SEQ ID NO: 18).
2. The method of claim 1 , comprising: contacting the composition to the contaminated drinking water to obtain partially purified water comprising coagulated or flocculated matter; removing at least part of the coagulated or flocculated matter from the partially purified water by sedimentation, filtration, decanting, flotation, or a combination thereof, to obtain purified water having at least a 90% reduction in turbidity.
3. The method of claim 1 , for the batchwise purification and clarification of a relatively small predetermined volume of contaminated drinking water, comprising: adding an effective amount of the composition in unit dosage form to the predetermined volume of contaminated water; dispersing the composition in the water to coagulate and flocculate suspended solid impurities therein; allowing the dispersed water to stand; and filtering the water to remove said impurities and to obtain purified water suitable for human consumption having at least a 90% reduction in turbidity.
4. The method of claim 1 , wherein the predetermined volume of water is in a range of 0.1 to 100 liters.
5. The method of claim 1 , wherein the predetermined volume of water is in a range of 0.5 to 2 liters.
6. The method of claim 1 , wherein the Bacillus cells comprise B. subtilis cells.
7. The method of claim 1 , wherein said signal peptide (SP) is YngK (SEQ ID NO: 5).