Modulating cultivation regimes of Messastrum gracile SVMIICT7 for biomass productivity integrated with resource recovery via hydrothermal liquefaction.

The present study was designed to assess Messastrum gracile SVMIICT7 potential in treating dairy wastewater (autoclaved (ADWW) and raw (DWW)) with relation to nutrient removal, in-vivo Chl-a-based biomass, and bio-oil synthesis. Chlorophyll a fluorescence kinetics revealed improved photochemical efficiency (0.639, Fv/Fm) in M. gracile when grown with DWW. This may be owing to enhanced electron transport being mediated by an effective water-splitting complex at photosystem (PSII) of thylakoids. The increase in ABS/RC observed in DWW can be attributed to the elevated chlorophyll content and reduced light dissipation, as evident by higher values of ETo/RC and a decrease in non-photochemical quenching (NPQ). M. gracile inoculated in DWW had the highest Chl-a-biomass yield (1.8 g L-1) and biomolecules while maximum nutrient removal efficiency was observed in ADWW (83.7% TN and 60.07% TP). M. gracile exhibited substantial bio-oil yield of 29.6% and high calorific value of 37.19 MJ kg-1, predominantly composed of hydrocarbons along with nitrogen and oxygen cyclic compounds. This research offers a thorough investigation into wastewater treatment, illustrating the conversion of algal biomass into valuable energy sources and chemical intermediates within the framework of a biorefinery.

Sustainable consideration for traditional textile handloom cluster/village in pollution abatement - A case study.

Decentralized handlooms are being traditionally practised throughout India. Siripuram village known for traditional Pochampally/Ikat work was considered as a case study for detailed investigation towards providing a sustainable solution. Nearly 65% of village population solely depend on weaving and dyeing works as primary occupation based on the household survey and generated wash water of 127 KLD on an average from the dyeing operations. Initially, a topographical survey (Aerial drone; PHANTOM 4 RTK UAV) was carried out to understand the drainage pattern, elevations, contours and interlinked with domestic and dyeing functions. The characteristics of combined wastewater and dye wash water were studied at lab scale using sequential batch (SBR) operation under aerobic (SBRAe) and aerobic-anoxic (SBRAex) microenvironments. SBRAex microenvironment showed effective organic and nutrients removal due to infused anoxic microenvironment. Treatment studies depicted 76.2% of organic fraction, 73.3% of phosphate, and 81.6% of nitrate removal. Based on the lab scale studies a closed-loop decentralized effluent treatment system was designed to ensure zero-liquid discharge (ZLD).

Polyhydroxybutyrate production by Chlorella sorokiniana SVMIICT8 under Nutrient-deprived mixotrophy.

Polyhydroxybutyrates (PHBs) are naturally occurring biopolymeric compounds that accumulate in a variety of microorganisms, including microalgae as energy and carbon storage sources. The present study was designed to evaluate nature-based PHB production using microalgae (Chlorella sorokiniana SVMIICT8) in biphasic (growth (GP) and stress phase (SP)) nutritional mode of cultivation. Microalgal PHB accumulation was driven by nutrient constraint, with a maximal production of 29.5% of PHB from 0.94 gm L-1 of biomass. Fluorescence microscopy revealed PHB granules in the cell cytoplasm, while NMR (1H and 13C), XRD and TGA analysis confirmed the structure. The biopolymer obtained was homopolymer of PHB with carbonyl (C=O) stretch of the aliphatic ester moiety. In GC-MS analysis, major peak representing butyric acid methyl ester also confirmed the PHB. Chlorophyll a fluorescence transients inferred through OJIP, exhibited significant variation in photosynthetic process during growth and nutrient limiting conditions. Mining of bio-based products from microalgae cultivation embrace nature-based approach addressing climate change and sustainability inclusively.

Phycoremediation potential ofTetradesmus sp.SVMIICT4in treating dairy wastewaterusingFlat-Panel photobioreactor.

Tetradesmus sp. SVMIICT4 was isolated and cultivated mixotrophically in a flat-panel photobioreactor (FP-PBR) for concurrent dairy wastewater treatment, carbon fixation, and biomass production. Integrated wastewater treatment showed good COD and nutrients removal efficiency accounting for biomass with an accumulation of carbohydrate (21.48 mg g-1) and protein (19.52 mg g-1). Chlorophyll a fluorescence transients (Fv/Fm, ETo/RC, TRo/RC, and Abs/RC) deduced through OJIP curve fittings, showed consistent improvement in photosynthetic activity throughout the cultivation period. The absorption flux per reaction centre corroborated with increased chlorophyll content (18.94 mg g-1), resulting in higher electron transport (ET/Rc) and lower non-photochemical quenching (NPQ). The fatty acid profile showed high content of unsaturated, followed by saturated fatty acids, which has multiple applications in food, feed, and fuel industries, enabling a bio-based economy.

Advances in microalgal research for valorization of industrial wastewater.

This review article focuses on recent updates on remediation of industrial wastewater (IWW) through microalgae cultivation. These include how adding additional supplements of nutrient to some specific IWWs lacking adequate nutrients improving the microalgae growth and remediation simultaneously. Various pretreatments strategy recently employed for IWWs treatment other than dealing with microalgae was discussed. Various nutrient-rich IWW could be utilized directly with additional dilution, supplement of nutrients and without any pretreatment. Recent advances in various approaches and new tools used for cultivation of microalgae on IWW such as two-step cultivation, pre-acclimatization, novel microalgal-bioelectrical systems, integrated catalytic intense pulse-light process, sequencing batch reactor, use of old stabilized algal-bacterial consortium, immobilized microalgae cells, microalgal bacterial membrane photobioreactor, low-intensity magnetic field, BIO_ALGAE simulation tool, etc. are discussed. In addition, biorefinery of microalgal biomass grown on IWW and its end-use applications are reviewed.

Photosynthetic transients in Chlorella sorokiniana during phycoremediation of dairy wastewater under distinct light intensities.

The present study is aimed to understand the photosynthetic transients of Chlorella sorokiniana SVMBIOEN2 during treatment of dairy wastewater under different light intensities (100, 150, and 200 µmol m-2s-1) in mixotrophic mode. Light intensities showed marked influence on photosystem behavior, lipid profile, and organic pollutant removal. Analysis of Chlorophyll a fluorescence transient including Fv/Fm, ETo/RC, TRo/RC, and Abs/RC showed better photosystem efficiency at 100 µmol m-2s-1 operations. OJIP curve fitting depicted a positive L-band at 150 µmol m-2s-1 indicating lower kinetic energy of photosystem II (PSII) reaction centres at high light intensities. Better photosynthetic activity at 100 µmol m-2s-1 operations resulted in good assimilation of biomass (2.3 g L-1), carbohydrates (10.2 mg g-1), and proteins (14 mg g-1) with a significant reduction in chemical oxygen demand (85%). Phycoremediation of dairy wastewater accumulates predominantly monounsaturated fatty acids followed by polyunsaturated fatty acids showing the application of C. sorokiniana in nutraceutical and food industries.