Characterization of a bioflocculant from a newly isolated Vagococcus sp. W31

Abstract

Screening of microorganisms producing flocculating substances was carried out. A strain secreting a large amount of bioflocculant was isolated from wastewater samples collected from the Little Moon River in Beijing. Based on the morphological properties and 16S rDNA sequence analysis, the isolate (designated W31) was classified as Vagococcus sp. A bioflocculant (named MBFW31) produced by W31 was extracted from the culture broth by ethanol precipitation and purified by gel chromatography. MBFW31 was heat-stable and had strong flocculating activity in a wide range of pH with relatively low dosage requirement. MBFW31 was identified as a polysaccharide with molecular weight over 2 x 10(6). It contained neutral sugar and uronic acid as its major and minor components, respectively. Infrared spectra showed the presence of hydroxyl, carboxyl and methoxyl group in its molecules. The present results suggested that MBFW31 had potential application in wastewater treatment.

Assessment of Bacillus pumilus Isolated from Fresh Water Milieu for Bioflocculant Production

“…The time course experiment was carried out following the method of Gao et al [24] with minor modifications. The bacterial strain was cultured under optimal culture conditions determined from previous experiments.…”

Production and Characterization of a Novel Bioflocculant from Bacillus licheniformis

“…Further analysis of the hydrolyzed bioflocculant revealed that the mass proportion of neutral sugar, amino sugar, and uronic acid was 7.9:4:1. Sufficient content of uronic acid in a bioflocculant molecule can provide carboxyl groups to the molecular chain, increasing the number of effective sites for adsorption of particles (10).…”

“…In spite of these studies, bioflocculants have not yet been produced industrially because of their comparatively low flocculating capability and high cost. Thus, the search for microorganisms with better flocculantproducing abilities and reduced production costs continues among researchers in this field (10,14).…”

Studies on Bioflocculant Production by Bacillus sp. AEMREG7

“…Contrary to the above, Zheng et al [35] found that the production of bioflocculant by Bacillus sp. F19 increases with an increase in cultivation time with the maximum flocculating activity reached after 36 h. In the findings of Gao et al [13], the flocculating activity of the bioflocculant produced by Vagococcus sp. W31 increased with cultivation time and reached maximum at 60 h.…”

“…Over the decades, many microorganisms, including bacteria, fungi, and algae have been reported to produce bioflocculants with different chemical compositions such as polysaccharide, protein, glycoprotein, and nucleic acids [12]. Gao et al [13] through several studies have been reported on bioflocculant production from different microbes [14], with high production cost being the major limiting factor for large-scale production for industrial applications [15,16]. Therefore, it would be economically favourable, as a cost-cutting measure, to utilize cost-effective substrates for bioflocculant production on an industrial scale [17].…”