TECHNOLOGY FOCUS - BIOTECHNOLOGY - Preferred Flocculant: In (I), the bacteria is of the species B.endophyticus, B.cereus or B.subtilis. The kaolin suspensions comprises 1.25% kaolin and 3% CaCl2.2H2O. The kaolin suspensions comprises 20 ml of 1.35% kaolin and 0.5 ml of 3% CaCl2.2H2O. The bacteria is contained in a bacterial solution comprising nutrient broth that has been incubated under 30degreesC and shaken for at least 15 hours. The bacterial solution has been shaken for at least 48 hours. The carbon source comprises glucose and molasses and the nitrogen source comprises soybean protein. The glucose is 10-20 g/l, molasses is 2-10 g/l, and soybean protein is 6-30 g/l. The carbon source comprises corn starch and molasses and nitrogen source comprises soybean protein. The corn starch is 10-20 g/l, the molasses is 5-10 g/l, and the soybean protein is 15 g/l. The carbon source comprises glucose and molasses and nitrogen source comprises soybean protein and yeast. In (II), the soybean protein has a concentration of 15-120 g/l. The soybean protein has been subjected to thermal treatments at 121degreesC, 1.5 atmosphere for 20 minutes.Preferred Methods: (M1) further involves subjecting the inoculated culture medium to high temperature treatment at 60-122degreesC, under high pressure such as 1.5 atmosphere. The culture medium is incubated for 70-80 or 90-100 hours. (M1) further involves precipitating out bacterial cells and/or metabolites and collecting the precipitates. In (M2), bacteria are incubated for 72-96 hours. The spray drying is set with an inlet temperature of 110degreesC and outlet temperature of 90degreesC. The culture medium comprises carbon source and nitrogen source. The carbon source comprises glucose and molasses and nitrogen source comprises soybean protein. The soybean protein is 15 g/l, glucose is 10 g/l and molasses is 5 g/l. The carbon source comprises cornstarch and nitrogen source comprises soybean protein. The soybean protein is 25 g/l and the corn starch is 10 g/l. EXAMPLE - Bacterial strains were separately incubated with 30 ml nutrient broth in 125 ml flasks, under 30degreesC, shaking in 200 rpm, for 15 hours. Then, 30 ml of the bacterial solution and 0.5 ml of 3% CaCl2.2H2O solution were added into 20 ml of 1.25% kaolin suspension. Then, the flocculating activity of the bacterial solution was analyzed by eye-measuring the turbidity differences between the supernatants of the kaolin suspension with the bacterial solutions and without the bacterial solution. From the preliminary screening, 50 microbial strains with the potential of producing biological flocculants were selected. The selected microbes were incubated with 100 ml nutrient broth in 500 ml round flasks, under 30degreesC, shaking at 200 rpm, for 48 hours. After the 48 hour incubation, the bacterial solution underwent high temperature treatment of 122degreesC and 1.5 atmosphere, followed by centrifugation under 4degreesC, 10000 rpm for 10 minutes to collect the bacterial cell precipitate. The collected bacterial cell precipitate was diluted by sterile water to a volume of 10 ml. Flocculation toward the kaolin suspension was examined by thoroughly mixing 5ml of the concentrated bacterial solution, 45 ml of tap water, 0.5 ml of 3% CaCl2.2H2O solution and 20 ml of 1.25% kaolin suspension. The mixture was then kept still for 30 minutes. Then, changes in the suspended particles in the mixture solution and volume of the settled sludge were observed. Through eye-measurement, five bacterial strains K0214, K0220, K3463, K5518 and Y2105-1 with the base flocculating capabilities and high recovery rate were selected as possible bacterial strains for producing the biological flocculants.