Abstract
This study evaluated the potential of a biopolymeric flocculant produced by Terrabacter sp. isolated from Sterkfontein Dam, South Africa. Microbial flocculants aid the aggregation of suspended solutes in solutions, thus, suggesting its alternative application to inorganic and synthetic organic flocculants, which are associated with health-related problems. The 16S rDNA analysis revealed the bacteria to have 98% similarity to Terrabacter sp. MUSC78T and the sequence was deposited in the Genbank as Terrabacter sp. with accession number KF682157.1. A series of experimental parameters such as bioflocculant dosage, cations concentrations, pH, and application of the purified bioflocculant in wastewaters treatment were investigated. In the presence of glucose as a sole carbon source, Ca2+ as cation at pH 8, the optimal flocculating activity attained was 85%. Optimum bioflocculant dosage of 0.5 mg/mL was able to remove chemical oxygen demand (COD), biological oxygen demand (BOD), suspended solids (SS), nitrate, and turbidity in dairy wastewater. In addition, the tested bioflocculant exhibited higher flocculating efficiency as compared to polyaluminum chloride, polyethylenime, and alum. Inductible coupled plasma optical emission spectroscopy (ICP-OES) analyses confirmed significant removal of 77.7% Fe, 74.8% Al, 61.9% Mn, and 57.6% Zn as representatives of heavy metals from treated dairy wastewater. Fourier transform infrared spectroscopy (FTIR) indicated the presence of carboxyl, hydroxyl, and amino groups in the purified bioflocculant which could be responsible for flocculation. Findings from this study showed the prospect of the studied bioflocculant as an alternative candidate in wastewater treatment and remediating of heavy metals.
Highlights
Increase in industrialization and anthropogenic activities has resulted in tremendous increases in the discharge of wastes and wastewater containing organic and inorganic pollutants into the environment [1]
We reported on the isolation, screening, and characterization of a bioflocculant produced by the actinomycete, Terrabacter sp. and its biotechnological application in wastewaters treatment and heavy metal removal
The slight decrease in flocculating activity at higher temperature could be due to the breaking down of the polysaccharide chain which could result into slow formation of bridges with the kaolin particles
Summary
Increase in industrialization and anthropogenic activities has resulted in tremendous increases in the discharge of wastes and wastewater containing organic and inorganic pollutants into the environment [1]. Wastewaters containing heavy metals are directly or indirectly discharged into the environment, and pose a serious threat to public health. Lead, and mercury are the most dangerous of these metals and they are known as toxic-trio metals. Murthy [2] reported that. Res. Public Health 2019, 16, 3337; doi:10.3390/ijerph16183337 www.mdpi.com/journal/ijerph
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