Shriniketan Puranik

Di-n-butyl phthalate (DBP) is one of the most extensively used plasticizers for providing elasticity to plastics. Being potentially harmful to humans, investigating eco-benign options for its rapid degradation is imperative. Microbe-mediated DBP mineralization is well-recorded, but studies on the pollutant’s fungal catabolism remain scarce. Thus, the present investigation was undertaken to exploit the fungal strains from toxic sanitary landfill soil for the degradation of DBP. The most efficient isolate, SDBP4, identified on a molecular basis as Aspergillus flavus, was able to mineralize 99.34% dibutyl phthalate (100 mg L⁻¹) within 15 days of incubation. It was found that the high production of esterases by the fungal strain was responsible for the degradation. The strain also exhibited the highest biomass (1615.33 mg L⁻¹) and total soluble protein (261.73 µg mL⁻¹) production amongst other isolates. The DBP degradation pathway scheme was elucidated with the help of GC-MS-based characterizations that revealed the formation of intermediate metabolites such as benzyl-butyl phthalate (BBP), dimethyl-phthalate (DMP), di-iso-butyl-phthalate (DIBP) and phthalic acid (PA). This is the first report of DBP mineralization assisted with A. flavus, using it as a sole carbon source. SDBP4 will be further formulated to develop an eco-benign product for the bioremediation of DBP-contaminated toxic sanitary landfill soils.

In the present investigation, nutritious and sugar- rich Banana pseudo stem core (BPS) served as a novel substrate for developing fermented beverages involving reference microorganisms, Saccharomyces ellipsoideus (RY4) and Lactobacillus acidophilus (RLAB4) along with other indigenous isolates of yeasts and lactic acid bacteria. The results indicated that the performance of the reference organisms was significantly better, as compared to BPS isolates. It was observed that beverage using RY4 produced highest alcohol content of 7.03% after 6 days. Further, a desirable microbial population for probiotic beverages was attained in RLAB4 (4.5 x 10⁶ cfu ml⁻¹ beverage). Additionally, treatment with RLAB4 also exhibited highest vitamin C (0.38 mg 100 ml⁻¹). Sensory evaluation disclosed that the beverages developed using the reference strains had better acceptability than their indigenous counterparts. The study also paves way for efficient utilization of voluminous biomass for the production of both alcoholic and non- alcoholic probiotic drinks, helping in valorization of the agro-residue.