The potency of microbial flocculant produced by B. licheniformis using molasses as the carbon source and its application in food industry wastewater treatment

Abstract

Flocculants play an important role in removing colloids, suspended particles, and dyes from industrial wastewater. Presently, synthetic flocculants have been widely applied in the industrial sector as colloidal aggregates. The use of these flocculants is known to harm human health and the environment for them being neurotoxic, strong carcinogens, and cannot be degraded by microbes. Therefore, bio-flocculants are an alternative to reduce the usage of synthetic flocculants. Moreover, studies on the application of food industry wastewater as food ingredients are increasingly being developed. It is estimated that the need for safe and biodegradable flocculants will also increase. This study was conducted to examine the production of bio-flocculants from Bacillus licheniformis using molasses as a carbon source under different molasses concentrations (15 g/l and 30 g/l) and incubation times (24, 48 and 72 h). The bio-flocculant from B. licheniformis was then applied to treat tofu industry wastewater for turbidity removal, reduction of Chemical Oxygen Demand (COD) and Biological Oxygen Demand (BOD). The highest flocculation rate of bio-flocculant was achieved at 46,62% to kaolin suspension by 15 g/l molasses within 24 h culture time. On the purification of tofu industry wastewater, the efficiency of turbidity removal of 15 g/l and 30 g/l molasses concentration variations were 70.03% and 43.04% respectively. Bio-flocculant produced also performed great BOD and COD removal by 75.9% and 80.2% which proceed by variation of 15 g/l molasses within 24 h incubation time. These high rate of turbidity, COD, and BOD removal by bio-flocculant indicates its effectiveness on industrial application in wastewater treatment.