Structural and Functional Characterization of a Lytic Polysaccharide Monooxygenase with Broad Substrate Specificity

The recently discovered lytic polysaccharide monooxygenases (LPMOs) carry out oxidative cleavage of polysaccharides and are of major importance for efficient processing of biomass. NcLPMO9C from Neurospora crassa acts both on cellulose and on non-cellulose β-glucans, including cellodextrins and xyloglucan. The crystal structure of the catalytic domain of NcLPMO9C revealed an extended, highly polar substrate-binding surface well suited to interact with a variety of sugar substrates. The ability of NcLPMO9C to act on soluble substrates was exploited to study enzyme-substrate interactions. EPR studies demonstrated that the Cu2+ center environment is altered upon substrate binding, whereas isothermal titration calorimetry studies revealed binding affinities in the low micromolar range for polymeric substrates that are due in part to the presence of a carbohydrate-binding module (CBM1). Importantly, the novel structure of NcLPMO9C enabled a comparative study, revealing that the oxidative regioselectivity of LPMO9s (C1, C4, or both) correlates with distinct structural features of the copper coordination sphere. In strictly C1-oxidizing LPMO9s, access to the solvent-facing axial coordination position is restricted by a conserved tyrosine residue, whereas access to this same position seems unrestricted in C4-oxidizing LPMO9s. LPMO9s known to produce a mixture of C1- and C4-oxidized products show an intermediate situation

Performance Evaluation and Upgradation of Existing Sugar Effluent Treatment Plant

Sugar industry is one of the most advanced agro based industries in India. The large quantity of wastewater generated at all stages of sugar production, poorly treated wastewater with high levels of pollutants caused by poor design, operation or maintenance of treatment systems creates major environmental problems, when such waste water is discharged to surface water or on land. The Maharashtra Pollution Control Board (MPCB) has prescribed based on the directions of the Central Pollution Control Board (CPCB) that the effluent generation in a sugar factory has to be limited to 1000 L/tons of cane crushed. Also as per CREP norms, certain provisions have been made for sugar factory effluent treatment as well. Considering the above stated implications an attempt has been to evaluate the performance of Effluent treatment plant (ETP) of Shri Ambalika Sugar Pvt. Ltd. in a district of Ahmednangar. This factory has provided and managed well equipped effluent treatment plant for handling 1000 m3/day. The plant is based on Activated Sludge process (ASP) principle. Samples were collected from six points in between raw waste water to multimedia filter outlet, i.e., treated effluent to evaluate the performance of ETP. The analysis was done at 15 days interval for three months. The parameters analyzed for evaluation of performance of ETP was pH, Total Solids (TS), Total Dissolved Solid (TDS), Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD3) @ 27°C, Oil and Grease, Chloride. Tests were performed to find the fate of pollutants in ETP. The present study shows that treated effluent is clear; Overall COD and BOD removal efficiency of ETP was more than 98% on an average. The oil and grease content is less than 0.5 mg/l, average TSS removal efficiency was 86%. And all other parameters are within consented limits stipulated by MPCB. As a result of this study, suggestion for improvement of the treatment efficiency by modification and provision of additional unit is given