Metabolism of polycyclic aromatic hydrocarbons by Aspergillus niger.

Aspergillus niger metabolised polycyclic aromatic hydrocarbons such as naphthalene, anthracene and phenanthrene. The maximum weight of mycelium was obtained at 8-10 days of incubation. TLC and HPLC analysis revealed the accumulation of metabolites in resting cell culture. The metabolism of naphthalene and anthracene follows the gentisate pathway, where as phenenthrene was metabolised via protocatechuate in this organism.

Degradation of 3-hydroxybenzoic acid by a Bacillus species.

A Bacillus sp. isolated by 4-hydroxybenzoate enrichment culture technique is capable of utilizing 3-hydroxybenzoate as the sole source of carbon and energy. The organism degraded 3-hydroxybenzoic acid through the intermediate formation of protocatechuic acid. 3-Hydroxybenzoate 4-hydroxylase, protocatechuate 3,4-dioxygenase and protocatechuate 4,5-dioxygenase activities were shown in cell-free extracts. The formed protocatechuate is metabolized through both the ortho and meta cleavage pathway.

Degradation of naphthalene by a Pseudomonas strain NGK1.

A Pseudomonas strain NGK1 capable of degrading naphthalene as a sole carbon source was isolated from biological waste treatment effluent. After 48 hr of incubation in 0.1% naphthalene mineral salts medium, the bacterial culture showed irregular clumped cells and salicylic acid (68 micrograms per ml) in the medium (pH 3.8). The strain degraded naphthalene through salicylate and catechol as was evidenced by metabolite characterization, oxygen uptake and enzymatic studies.