Flocculating Properties of a Bioflocculant Produced by Bacillus sp. Isolated from a Marine Environment in South Africa

We assessed the bioflocculant production by a bacteria isolated from a marine environment in South Africa. The 16S rDNA nucleotide sequence analyses revealed the bacteria to have a 99 % similarity to Bacillus sp. A-5A and the sequence was deposited in the Genbank as Bacillus sp. MAYA (accession number JF799093). Bioflocculant production by the bacteria was optimal when glucose (95.6 % flocculating activity) and ammonium nitrate (83.3 % flocculating activity) were used as carbon and nitrogen sources respectively; inoculum size was 2 % (v/v); initial pH 6; and Ca2+ as coagulant aid. Chemical analysis of the purified bioflocculant shows that it is composed of uronic acid, neutral sugar and protein. FTIR analysis reveals the presence of methoxyl, hydroxyl, carboxyl and amino-groups in the compound bioflocculant. The bioflocculant is thermostable with about 65.6 % residual flocculating activity retained after heating the bioflocculant at 100 °C for 25 minutes