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Over the last century, contamination of polycyclic aromatic hydrocarbons (PAHs) has risen tremendously due to the intensified industrial activities like petrochemical, pharmaceutical, insecticides and fertilizers applications. PAHs are a group of organic pollutants with adverse effects on both humans and the environment. These PAHs are widely distributed in various ecosystems including air, soil, marine water and sediments. Degradation of PAHs generally occurs through processes like photolysis, adsorption, volatilization, chemical degradation and microbial degradation. Microbial degradation of PAHs is done by the utilization of diverse microorganisms like algae, bacteria, fungi which are readily compatible with biodegrading/bio transforming PAHs into H2O, CO2 under aerobic, or CH4 under anaerobic environment. The rate of PAHs degradation using microbes is mainly governed by various cultivation conditions like temperature, pH, nutrients availability, microbial population, chemical nature of PAHs, oxygen and degree of acclimation. Several microbial species including Selenastrum capricornutum, Ralstonia basilensis, Acinetobacter haemolyticus, Pseudomonas migulae, Sphingomonas yanoikuyae and Chlorella sorokiniana are known to degrade PAHs via biosorption and enzyme-mediated degradation. Numerous bacterial mediated PAHs degradation methods are studied globally. Among them, PAHs degradation by bacterial species like Pseudomonas fluorescence, Pseudomonas aeruginosa, Rhodococcus spp., Paenibacillus spp., Mycobacterium spp., and Haemophilus spp., by various degradation modes like biosurfactant, bioaugmentation, biostimulation and biofilms mediated are also investigated. In contrarily, PAHs degradation by fungal species such as Pleurotus ostreatus, Polyporus sulphureus, Fusarium oxysporum occurs using the activity of its ligninolytic enzymes such as lignin peroxidase, laccase, and manganese peroxidase. The present review highlighted on the PAHs degradation activity by the algal, fungal, bacterial species and also focused on their mode of degradation.

Polyhydroxybutyrate (PHB) accumulating Bacillus megaterium was isolated from marine water. To increase the PHB productivity by Bacillus megaterium, steps were taken to evaluate the effects of carbon sources (arabinose, glucose, glycerol, lactose, lactic acid, mannitol, sodium acetate, starch and sucrose at a level of 20 g/L), nitrogen sources (ammonium chloride, ammonium sulphate, glycine, potassium nitrate, protease peptone and urea at a level of 2 g/L) and different pH. A maximum yield of 2.74 g/L of PHB was achieved for glucose as the carbon source and ammonium sulphate as the nitrogen source at pH 7. The optimized conditions were further used for batch fermentation throughout 72 h. Significantly maximum PHB of 5.61 g/L was obtained in a laboratory scale bioreactor at 64 h. The extracted polymer was compared with the authentic PHB and was confirmed to be PHB using FTIR, 1H NMR, DSC and TGA analysis, respectively.