Removal Of Pollutants By Filamentous Bacterial Cells

Source: doi.org/10.1007/s13762-020-02918-3

At present, for removing waste materials from sewage and effluent, several types of organic and inorganic flocculants, such as polyacrylamide, FeCl₃, and AlCl₃, are used in wastewater treatment systems. Although these flocculants are effective and low-cost processes, their toxicity and non-biodegradability are shortcomings. Recently, bioflocculants and biosorbents consisted of biological materials have attracted attention because of their non-toxicity and biodegradability. However, the high production cost resulting from their complicated preparation process is a limiting factor of its practical application. To solve the problems, we performed to provide a novel bioflocculant/biosorbent consisted of dead cells of a marine filamentous bacterium, Aureispira sp. CCB-QB1 (referred to hereafter as QB1). By the way, why did we focus on the QB1 cells? Previous our study demonstrated that the QB1 cells are able to show the cell aggregation and capture its bacterial prey in the presence of calcium ion (Ref.1). Based on the results, we expected that the QB1 cells are capable of adsorbing the pollutants. Current results showed that the dead cells exhibited robust adsorption activity on kaolin clay particles (inorganic material). A diazo dye, Congo red were removed from the solutions in the presence of 50 mM CaCl₂. In addition, heavy metals, such as Fe³⁺ and Cu²⁺ (< 50 mg/L), were also quickly removed (after a10-min incubation period) form the solutions. These indicate that the QB1 cells are a multifunctional bioflocculant/biosorbent. Besides that, the preparation process of the QB1 is more straightforward than those of known bioflocculants and biosorbents, indicating that the production cost may be cheaper than known bioflocculants and biosorbents. Thus, we believe that our novel product has a potential alternative for known flocculants/sorbents in wastewater treatment systems.




Reference
G. Furusawa, P. Hartzell and V. Navaratnam (2015) Calcium is required for ixotrophy of Aureispira sp. CCB-QB1.  Microbiology 161, 1933-1941