Brazilian Journal of Microbiology Brazilian Journal of Microbiology
Braz J Microbiol 2018;49:731-41 - Vol. 49 Num.4 DOI: 10.1016/j.bjm.2017.02.013
Environmental Microbiology
Bioflocculant production from Streptomyces platensis and its potential for river and waste water treatment
Mayowa Agunbiadea,b, Carolina Pohlb, Omotayo Ashafaa,,
a University of the Free State, Qwaqwa Campus, Department of Plant Sciences, Phytomedicine and Phytopharmacology Research Group, Phuthaditjhaba, South Africa
b University of the Free State, Department of Microbial, Biochemical & Food Biotechnology, Bloemfontein, South Africa
Received 04 October 2016, Accepted 11 February 2017
Abstract

A bacterium isolated from Sterkfontein dam was confirmed to produce bioflocculant with excellent flocculation activity. The 16S rDNA nucleotide sequence analyses revealed the bacteria to have 99% similarity to Streptomyces platensis strain HBUM174787 and the sequence was deposited in the Genbank as Streptomyces platensis with accession number FJ 486385.1. Culture conditions for optimal production of the bioflocculant included glucose as a sole carbon source, resulting in flocculating activity of 90%. Other optimal conditions included: peptone as nitrogen source; presence of Mg2+ as cations and inoculum size of 1.0% (v/v) at neutral pH of 7. Optimum dose of the purified bioflocculant for the clarification of 4g/L kaolin clay suspension at neutral pH was 0.2mg/mL. Energy Dispersive X-ray analysis confirmed elemental composition of the purified bioflocculant in mass proportion (%w/w): carbon (21.41), oxygen (35.59), sulphur (26.16), nitrogen (0.62) and potassium (7.48). Fourier Transform Infrared Spectroscopy (FTIR) indicated the presence of hydroxyl, carboxyl, methoxyl and amino group in the bioflocculant. The bioflocculant produced by S. platensis removed chemical oxygen demand (COD) in river water and meat processing wastewater at efficiencies of 63.1 and 46.6% respectively and reduced their turbidity by 84.3 and 75.6% respectively. The high flocculating rate and removal efficiencies displayed by S. platensis suggests its industrial application in wastewater treatment.

Keywords
Culture conditions, Polysaccharide, Flocculating activity, Kaolin suspension, EDX & FTIR
Braz J Microbiol 2018;49:731-41 - Vol. 49 Num.4 DOI: 10.1016/j.bjm.2017.02.013