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Seven aerobic bacterial strains were isolated from pulp paper mill waste and screened for pentachlorophenol (PCP) tolerance on PCP containing mineral salt agar medium (MSM). The organism was characterized by 16S rDNA sequencing which showed 99.7% sequence similarity with Serratia marcescens. PCP degradation was routinely monitored with spectrophotometric analysis and further confirmed by HPLC analysis. Among seven strains, ITRC S7 was found to degrade up to 90.33% of 1.127 mM (300 mg/l) of PCP and simultaneous release of chloride ion (2.435 mM) emphasized the bacterial dechlorination in the medium in presence of glucose as an additional carbon and energy source under optimized condition within 168 h incubation. In absence of glucose bacterium was unable to utilize PCP indicating the phenomenon of co-metabolism. Bacterium was identified as S. marcescens (AY927692), was a novel and potential aerobic bacterial strain capable of degrading PCP in axenic condition. Further, this strain may be used for bioremediation of PCP containing pulp paper mill waste in the environment.

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The consortium of Bacillus cereus (DQ002384), Serratia marcescens (AY927692) and Serratia marcescens (DQ002385) were used for pentachlorophenol (PCP) degradation. The consortia showed better overall removal efficiencies than single strains by utilization of PCP as a carbon and energy source confirmed by pH dependent dye indicator bromocresol purple (BCP) in mineral salt media (MSM). Mixed culture was found to degrade up to 93% of PCP (300 mg/l) as compared to single strains (62.75-90.33%), at optimized conditions (30 ± 1°C, pH 7 ± 0.2, 120 rpm) at 168 h incubation. PCP degradation was also recorded at 20°C (62.75%) and 37°C (83.33%); pH 6 (70%) and pH 9 (75.16%); 50 rpm (73.33%) and 200 rpm (91.63%). The simultaneous release of chloride ion up to 90.8 mg/l emphasized the bacterial dechlorination in the medium. GC-MS analysis revealed the formation of low molecular weight compound, i.e., 6-chlorohydroxyquinol, 2,3,4,6-tetrachlorophenol and tetrachlorohydroquinone, from degraded sample as compared to control.

Lichens are known to synthesize a variety of secondary metabolites having multifunctional activity in response to external environmental condition. Two common lichen extrolites, atranorin and salazinic acid, are known to afford antioxidant as well as photoprotectant nature depending on the abiotic/biotic stress. The present investigation aims to study the influence of altitudinal gradient on the quantitative profile of atranorin and salazinic acid in three lichen species, Bulbothrix setschwanensis (Zahlbr.) Hale, Everniastrum cirrhatum (Fr.) Hale and Parmotrema reticulatum (Taylor) Choisy, Parmeliaceae using liquid chromatography-mass spectrometry (LC-MS/MS) technique. Samples were collected from high-altitude area, usually considered as non-polluted sites of Garhwal Himalaya. Characterization and quantification of the lichen substances in samples were carried out comparing with the standards of atranorin and salazinic acid. Results indicated significant variation in the chemical content with the rising altitude. All the three lichen species showed higher quantities of chemical substances with the altitudinal rise, while among the three lichen species, E. cirrhatum showed the highest quantity of total lichen compounds. The higher abundance and frequency of E. cirrhatum with increasing altitude as compared to B. setschwanensis and P. reticulatum may be attributed due to the presence of higher quantity of photoprotecting/antioxidant chemicals especially salazinic acid. Thus, the present study shows the prominent role of secondary metabolite in wider ecological distribution of Parmelioid lichens at higher altitudes.