A Marine Bacterium, Bacillus sp. Isolated from the Sediment Samples of Algoa Bay in South Africa Produces a Polysaccharide-Bioflocculant

Abstract

Bioflocculants mediate the removal of suspended particles from solution and the efficiency of flocculation is dependent on the characteristics of the flocculant. Apart from the merits of biodegradability and harmlessness, bioflocculants could be viable as industrially relevant flocculants as they are a renewable resource. Additionally, the shortcomings associated with the conventionally used flocculants such as aluminium salts and acrylamide polymers, which include dementia and cancer, highlight more the need to use bioflocculants as an alternative. Consequently, in this study a marine sediment bacterial isolate was screened for bioflocculant production. Basic local alignment search tools (BLAST) analysis of 16S ribosomal deoxyribonucleic acid (rDNA) sequence of the bacterial isolate showed 98% similarity to Bacillus thuringiensis MR-R1. The bacteria produced bioflocculant optimally with inoculum size (4% v/v) (85%), glucose (85.65%) and mixed nitrogen source (urea, ammonium chloride and yeast extract) (75.9%) and the divalent cation (Ca2+) (62.3%). Under optimal conditions, a maximum flocculating activity of over 85% was attained after 60 h of cultivation. The purified polysaccharide-bioflocculant flocculated optimally at alkaline pH 12 (81%), in the presence of Mn2+ (73%) and Ca2+ (72.8%). The high flocculation activity shown indicates that the bioflocculant may contend favourably as an alternative to the conventionally used flocculants in water treatment.

Exploration of Performance Kinetics and Mechanism of Action of a Potential Novel Bioflocculant BF-VB2 on Clay and Dye Wastewater Flocculation

“…This complies with polysaccharide bioflocculant produced by B. licheniformis and Bacillus sp. (Chen et al, 2017b; Ntozonke et al, 2017). The bioflocculant BF-VB2 was subjected to HPLC for compositional analysis.…”

Removal of Pollutants in Mine Wastewater by a Non-Cytotoxic Polymeric Bioflocculant from Alcaligenes faecalis HCB2

“…The 20 g/L of glucose used in the original medium was replaced with various carbon sources (sucrose, maltose, starch, fructose, lactose, and molasses) for determination of their effect on flocculating activity. Various nitrogen sources (peptone, urea, yeast, ammonia, and casein) of 1.2 g/L, were utilized individually in the medium and flocculating activity determined [9]. The mixing speeds in a range of 0–220 rpm, pH of the culture medium (3–12), cultivation temperatures (20–50 °C) were also varied, respectively.…”

“…Moreover, they possess un-hydrolysable bonds, which render them undegradable [8]. Therefore, due to the drawbacks of the inorganic and synthetic flocculants, biological wastewater treatment agents such as bioflocculants, have recently gained attention [9]. Bioflocculants are macromolecular polymers of carbohydrates, proteins, lipids or nucleic acids secreted by microorganisms during metabolic processes [10].…”

Isolation, Identification and Characterization of Bioflocculant-Producing Bacteria from Activated Sludge of Vulindlela Wastewater Treatment Plant

“…However, some disadvantages have been noted as well, one of which is that they have been reported to cause Alzheimer's disease, cancer and other debilitating illnesses [8]. Furthermore, acrylamide and amine polymers are resistant to biodegradation [9], with all attempts at degradation resulting in the reduction of the polymers to monomeric units, which may eventually percolate into sediments or water beds and possibly seep into underground waters [6][7][8][9][10]. The presence of acrylamide monomeric units and amine polymers derivatives in the environment constitutes a serious major health concern [10].…”

“…Furthermore, acrylamide and amine polymers are resistant to biodegradation [9], with all attempts at degradation resulting in the reduction of the polymers to monomeric units, which may eventually percolate into sediments or water beds and possibly seep into underground waters [6][7][8][9][10]. The presence of acrylamide monomeric units and amine polymers derivatives in the environment constitutes a serious major health concern [10]. However, bioflocculants have not been associated with any negative health effects [11].…”