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Fossil fuels are sharing a large portion of energy demand. Conventional energy sources emit a huge amount of greenhouse gas into the atmosphere, which creates energy and environmental challenges for the ecosystem. To fulfill the world energy demand and to support environmental as well as economic development in a sustainable way, with the utilization of technological advancement of renewable energy resources, algae are presently believed as most adaptable feedstock materials for bioenergy production. Algae has a high fixation rate of atmospheric carbon dioxide which supports to fast growth rate with high productivity per unit area in the form of renewable algal biomass. The present article aims to elaborate on the three generations of biofuels, sustainable microalgae biomass production, cultivation systems, and a wide range of growth parameters. The microalgae harvesting methods and their challenges are also discussed, with a special focus on lipid extraction methods and future r recommendations. The upstream and downstream processes of microalgae could help to harness the microalgae energy in an eco-friendly manner and will help in achieving overall sustainable development.

Population detonation and inflated demand for agricultural products have resulted in the rampant use of pesticides in recent years. These pesticides are used to reduce the number of pesticides by different mechanisms. They have been utilized in agriculture to expand agrarian profit, crop yield, quality, and storage life. The incessant and extensive use of resistant pesticides has contaminated the water bodies, fields, crops, and aquatic biota as well as poses a threat to human health. As a result, stringent regulations and limits are established to monitor the pesticide matrix. The current review focuses on pesticide contamination in the food chain, particularly from the aquatic bodies to fishes and humans. It also discusses strict regulations and limits including maximum residual limits for food items, acceptable daily intake, theoretical maximum daily intake, and estimated carcinogenicity/non-carcinogenicity for fishes and human health risks. In addition to conferring the negative effects of pesticides, this article discusses cost-effective remediation techniques such as phytoremediation, adsorption, the Fenton oxidation method, microalgal/high-rate algal ponds, and nanotechnology with the comparison of their remediation cost.

Lignocellulosic biomass generated from different sectors (agriculture, forestry, industrial) act as biorefinery precursor for production of second-generation (2G) bioethanol and other biochemicals. The integration of various conversion techniques on a single platform under biorefinery approach for production of biofuel and industrially important chemicals from LCB is gaining interest worldwide. The waste generated on utilization of bio-resources is almost negligible or zero in a biorefinery along with reduced greenhouse gas emissions, which supports the circular bioeconomy concept. The economic viability of a lignocellulosic biorefinery depends upon the efficient utilization of three major components of LCB—cellulose, hemicellulose and lignin. The heterogeneous structure and recalcitrant nature of LCB is main obstacle in its valorization into bioethanol and other value-added products. The success of bioconversion process depends upon methods used during pre-treatment, hydrolysis and fermentation processes. The cost involved in each step of the bioconversion process affects the viability of cellulosic ethanol. The lignocellulose biorefinery has ample scope, but much-focused research is required to fully utilize major parts of lignocellulosic biomass with zero wastage. The present review entails lignocellulosic biomass valorization for ethanol production, along with different steps involved in its production. Various value-added products produced from LCB components were also discussed. Recent technological advances and significant challenges in bioethanol production are also highlighted in addition to future perspectives. Graphical abstract

Green synthesis of metallic nanoparticles using plant sources has become an excellent substitute for conventional chemical synthetic methods. Nowadays, nano biotechnology is growing at a very fast rate due to its various possible application in the pharmaceutical biomedical, textile, paper industries. In our study, we have reported the green synthesis of chalcogenide nanostructure pharmacologically active chromium oxide (Cr2O3) nanoparticles using synthesized chromium (III) complex as a single route precursor. The synthesized chromium (III) complex was reacted with an aqueous extract of cinnamon bark for the green synthesis of Cr2O3 nanoparticles. In the present study, we aimed to synthesize chromium oxide nanoparticles (Cr2O3 NPs) through a facile low-cost, eco-friendly route. In this method, we use the aqueous environment for green synthesize of Cr2O3 NPs because the use of an aqueous medium plays a very important role in reducing time, reducing minimum possibilities of side reactions and proper execution of conversions of synthesized Cr(III) complex into a good quality of Cr2O3 NPs in a very less time. The synthesized chromium (III) complex and green synthesized Cr2O3 NPs were thoroughly analyzed through various structural, morphological, electronic, vibrational and pharmacological characterization techniques. Powdered X-ray diffraction studies confirm the formation of well-defined equip spaced crystalline nanoparticles of chromium oxide. Transmission electron microscopy exhibits oval-shaped structure of Cr2O3 NPs with an average particle size of 48 nm. Sharp electronic absorptions ends at 345nm for Cr(III) complex and at 429nm indicates the synthesis of good quality of chromium(III) complex and Cr2O3 NPs. The FT-IR spectral studies confirmed the presence of Cr-O stretching, N-H bonding and C=O stretching vibrations in synthesized Cr(III) complex was performed to investigate the thermal stability of the complex. The Cr(III) complex is stable up to 350ºC. The effective pharmacological activities like in vitro antimicrobial and antioxidant activities explained the presence of strong electron-withdrawing and electronwithdrawing groups in synthesized chromium (III) complex. The green synthesis of Cr2O3 NPs via aqueous extract of cinnamon back in proper stoichiometric ratio is a good method for synthesizing highly effective bioactive agents which will be considered as a good drug candidate for various biological applications in future for various biomedical applications

Transition metal complexes of Ni (II) with schiff base ligand (HL) derived from condensation of 3-Bromo benzaldehyde and hydrazine monohydrate were successfully synthesized , characterized and isolated .The schiff base ligand and its Ni(II) complexes prepared were characterized by melting point /decomposition temperature, solubility, conductivity/ Molar conductance, UV- visible, FT-IR, XRD, TGA and elemental analysis results. In the UV-Vis study, a bathochromic shift of approximately 60 nm indicating the formation of coordinated Ni(II) complexes by more than one coordinating sites . IR spectra of the free ligand showed a band at 1660cm-1 which is assigned to the (-C=N-) stretching vibration of the azomethine functional group. These bands were observed at lower frequencies in the spectra of Ni(II) complexes which indicates complexation process between schiff base ligand and Ni2+ ion . Low conductance (7-9 ohm-1 cm2 Mol-1) measurement indicated that the Ni (II) complexes are non electrolytic in nature whereas elemental analysis result revealed 1:1 Nickel-schiff base ratio. TGA analysis showed the presence of two coordinated water molecules on the basis of physico chemical measurements the following empirical formulas have been assigned to coordinated Ni(II) complex : [ Ni(HL)2 ] 2Cl. 2H2O, [ Ni(HL)2 ] SO4 .2H2O. The antioxidant activities of schiff base ligand and Ni(II) complexes were evaluated by using DPPH reagent ie, 2, 2’- diphenyl -1-picrylhydrazyl free radical assay which showed that coordinated Ni(II) complexes have a higher antioxidant activities than that of Schiff base ligand. All compounds have been evaluated for invitro anti microbial activities against isolated bacterial strains of E. coli (MTCC-1687), E. faecalis (MTCC-439), S. aureus (MTCC-737) and MR S. aureus (Indigenous) .All compounds showed mild to moderate antibacterial activities. The minimum inhibitory concentration values ranged from 50 g/ml to 3.125 g/ml. All compounds displayed invitro anti bacterial activity against both gram positive and gram negative bacterial strains. It may be proved that the antibacterial activity of compounds is related to the cell wall structure of the tested bacterial stain. The synthesis of Ni(II) complexes via template method is a good method for obtaining very efficient bioactive agents as a good drug candidates for various biological applications in future for humans. As well as schiff base molecular adducts of Ni(II) complexes are also promising material in different cutting edge research areas like applications in preparation of solar cells, super capacitors, catalysts and electrode materials. Keywords: Schiff base ligands, Ni(II) complexes, Spectroscopic analysis, antioxidant activities, Antimicrobial activities, DPPH, 3-Bromobenzaldelyde

Refereed/Peer-reviewed In this review article, waste materials (biogenic/non-biogenic) are focused as the flocculants for harvesting of algal biomass. Chemical flocculants are widely utilized for the effective harvesting of algal biomass at a commercial scale while the high cost is a major drawback. The waste materials-based flocculants (WMBF) are started to utilize as one of the cost-effective performance for dual benefits of waste minimization and reuse for sustainable recovery of biomass. The novelty of the article is articulated with the objective that presents an insight of WMBF, classification of WMBF, preparation methods of WMBF, mechanisms of flocculation, factors affecting flocculation-mechanism, challenges and future recommendations that are required for harvesting of algae. The WMBF are shown similar flocculation mechanisms and flocculation efficiencies as chemical flocculants. Thus, the utilization of waste material for the flocculation process of algal cells minimizes the waste load into the environment and transforms the waste materials into valuable resources.

The efficient management and treatment of pharmaceutical industry wastewater (PIWW) have become a serious environmental issue due to its high toxicity.To overcome this problem, the present study deals with the phycoremediation of PIWW using Chlorella vulgaris microalga isolated from the Ganga River at Haridwar, India. For this, response surface methodology (RSM) and artificial neural network (ANN) tools were used to identify the best reduction of total phosphorus (TP) and total Kjeldahl’s nitrogen (TKN) based pollutants along with lipid production efficiency of C. vulgaris. Three different concentrations of pharmaceutical wastewater (0, 50, and 100%), operating temperatures (20, 25, and 30°C), and light intensity (2000, 3000, and 4000 lx)were used to design the phycoremediation experiments. Findings revealed thatC.vulgaris was good enough to remove maximum TP (90.35%), TKN (83.55%) along 20.88% of lipid yield at 25.62℃ temperature, 60.73% PIW concentration, and 4000 lx of light intensity, respectively.Based on the model performance and validation results, ANN showed more accuracy as compared to the RSM tool. Therefore, the findings of this study showed thatC.vulgarisis capable of treating PIWW efficiently along with significant production of lipid content which can further be used in various applications including biofuels production.

Pollution-free rivers give indication of a healthy ecosystem. The stretch of Tawi river particularly in the Jammu city is experiencing pollution load and the quality is degraded. The present study highlights the impact of COVID-19 lockdown on the water quality of Tawi river in Jammu, J&K Union Territory. Water quality data based upon the real-time water monitoring for four locations (Below Tawi Bridge, Bhagwati Nagar, Belicharana and Surajpur) have been obtained from the web link of Jammu and Kashmir Pollution Control Board. The important parameters used in the present study include pH, alkalinity, hardness, conductivity, BOD and COD. The river was designated fit for bathing in all the monitoring locations except Bhagwati Nagar which recorded a BOD value >5 mg/L because of domestic sewage and municipal waste dumping. The overall water quality in the river during lockdown was good and falls in Class B with pH (7.0-8.5), alkalinity (23.25-185.0 mg/L), hardness (84.25-177.5 mg/L), conductivity (117-268 ms/cm). The improved water quality obtained during lockdown is never long-lasting as evident from the BOD and COD values observed during Unlock 1.0 due to accelerated anthropogenic activities in response to overcoming the economic loss, bringing the river water quality back to the degraded state. The statistical analysis known as cluster analysis has also been performed to evaluate the homogeneity of various monitoring sites based on the physicochemical variables. The need of the hour is to address the gaps of rejuvenation strategies and work over them for effective river resiliency and for sustainable river basin management.

Becker muscular dystrophy (BMD) is an X-linked recessive disorder involving mutation of the dystrophin gene. Cardiac involvement in BMD is frequent and represents the foremost cause of mortality. Two male siblings with severe left ventricular (LV) dysfunction and presence of deletion in the dystrophin gene underwent cardiac magnetic resonance (CMR) imaging, which revealed typical but varying imaging findings. The CMR revealed dilated left ventricle with severe global hypokinesis with preserved right ventricular (RV) function. Few patchy areas of septal edema were seen with typical epicardial enhancement along the LV lateral wall and the RV side of septum in one sibling. Both the siblings revealed an elevated myocardial native T1 values. CMR has the potential to detect cardiac involvement early by identifying and quantifying fibrosis, before wall motion abnormalities set in and determine prognosis in patients with muscular dystrophy and BMD carriers.

Background: Coronary artery disease (CAD) is a major cause of morbidity and mortality in India. Stress Cardiac Magnetic Resonance (CMR) using vasodilator agent is well established in assessing the functional significance of CAD. Adenosine is the preferred agent, but can have severe side effects including dyspnoea, chest pain, atrioventricular block or bronchospasm. The stress CMR examination is not routinely performed in many of the clinical imaging departments in India. Objective: The aim of this study was to establish safety of adenosine as a pharmacological stressor agent for CMR in a tertiary care radiology department in India. Methods: A review of all patients undergoing stress CMR in our institution from May 2018 to May 2019 was made. Records were reviewed to collect response parameters and documented adverse reactions. Results: A total of 1057 patients underwent stress CMR during this period. No death, myocardial infarction or atrio-ventricular block related complications were seen. Transient hypotension was seen in 20 patients (1.8’) with spontaneous recovery after stopping infusion. Chest pain and breathlessness severe enough to discontinue the scan were seen in 6 (0.5’) and 10 (0.9’) patients, respectively. All patients with breathlessness recovered on low flow oxygen therapy with three requiring bronchodilator. Out of six patients with chest pain, three had immediate relief with sublingual nitroglycerin, and three required hospital admission for unstable angina. Of the latter three, 1 underwent revascularization on the same day and other two later in the week. Conclusion: Stress CMR using adenosine in appropriately selected patients is a highly safe procedure with significant side effects seen in less than 1’ of patients. Therefore, it is safe to perform stress CMR studies in a fully equipped and well-trained radiology department in India.

Most of the Indian rural area is electrified now, but the gap between supply and demand is much greater and increasing due to rapid industrial growth and increase in rural as well as urban living standards. That cause the extra burden on power grid. In order to reduce the burden on the national grid, India is moving fast towards distributed generation, and various studies show that renewable-based micro-grid is a preeminent alternative for decentralized energy generation. Most of the Indian population live in rural areas with access to wide varieties of alternative energy sources (wind, solar, hydro, biomass, etc.). Therefore, to reduce the dependency on heavily loaded power grid, a hybrid renewable energy system is required by utilizing the locally available sources, which incorporates more than one source of energy by combining the benefits and strength of one source to complement each other. This paper proposed a PV-Biomass-Grid-based optimal micro-grid system, based on locally available resources in Kashmir region of Jammu and Kashmir, India. In the proposed micro-grid, load is served on the basis of priorities to employ minimum burden on the grid and increase the use of renewable resources. The overall goal of the study is to minimize the cost of energy and maximize the energy output from hybrid renewable energy system. Extra electricity generated beyond the load demand would be supplied to grid. In this way, system energy cost is reduced with improvement in electrical system and reducing the environmental impact.

The trillions of microbes that colonize and live around us govern the health of both plants and animals through a cascade of direct and indirect mechanisms. Understanding of this enormous and largely untapped microbial diversity has been the focus of microbial research from the past few decades or so. Amidst the advancements in sequencing technologies, significant progress has been made to taxonomically and functionally catalogue these microbes and also to establish their exact role in the health and disease state. In comparison to the human microbiome, plants are also surrounded by a vast diversity of microbes that form complex ecological communities that affect plant growth and health through collective metabolic activities and interactions. This plant microbiome has a substantial influence on human health and environment via its passage through the nasal route and digestive tract and is responsible for changing our gut microbiome. This review primarily focused on the advances and challenges in microbiome research at the interface of plant and human, and role of microbiome at different compartments of the body’s ecosystems along with their correlation to health and diseases. This review also highlighted the potential therapies in modulating the gut microbiota and technologies for studying the microbiome.

Rapid growth in industrialization has led to high dependency of reliable electric power source for its operation. On the contrary, thermal power plants expel pollutants consisting of hazardous gases that result in degradation of environment and ecosystem. Thus, utmost importance is to generate clean and efficient energy from power plant. This current article resolves the problem of sustainable power production using coal-based thermal power plants, by integrating gasification technologies to the system. The performance of thermal power plant in terms of emission is numerically analyzed with varying gasifier pressure, air-fuel ratio, steam-fuel ratio and flue gas-fuel ratio. Numerical simulation of the gasification cycle with varying parameters is carried out using MATLAB. Optimum performance at gasifier pressure of 2 bar and the steam-fuel ratio of 0.25 was observed with relative air-fuel of 0.075. With increasing flue gas-fuel ratio from 0.25 to 1.00, although the mole fractions of components of syngas don’t differ much, the heating value and cold-gas efficiency of syngas produced decreases for each fuel. Considering the emissions, simulated results present co-gasification as better option over conventional systems. A reduction of two-third in kg of CO2 released per kg of fuel was observed with almost three-fourth decrement in kg of CO2 per kWh of power produced. Also, zero SOx and NOx emissions were observed compared to coal based thermal power plants. It is noted that optimum performance of gasification system at gasifier pressure of 2 bar, air-fuel ratio of 0.1, steam-fuel ratio of 0.25 and flue gas-fuel ratio of 1.00. The proposed cycle presents itself suitable for further research and its application to coal based thermal power plants, providing potential towards supplementary power generation and cleaner exhaust. This research would also significantly contribute to achieve sustainable development goals.

Rate of energy production is reflecting growth of nations and most of energy produced from the coal and natural gas-based thermal power plants (TPPs). Flue gas (point sources of emission) are main exhaustible form of gases that come from thermal power plants and are continuously promoting climate change and various environmental problems in global scenario. The present available technologies of flue gas treatment are energy and cost-intensive process. Among the available techniques for fixation of flue-gases at sustainable part, microalgal bio-fixation of flue gas is an alternative promising and competent technology with assurance of eco-friendly path of low energy and low-cost solution for pollution abetment with production of value added products. According to mechanism involves during photosynthetic process of microalgae, it utilizes atmospheric CO2 and CO2 from flue gases for their growth. Past, present and future treatment technologies for flue gas with their challenges are discussed. Recent experimental studies and commercially available bioreactors are very particular for bio-fixation of flue gas from thermal power plants are also reviewed with their future perspectives. The commercial viability of process with specific microalgal strains and utilized biomass for further value-added products are suggested with future limitations.

An experimental study was performed to evaluate the comparative efficiency of bio-flocculant (waste egg shell), laboratory available calcium carbonate (LACC) and alum (Al2 (SO4)3) for harvesting of unicellular microalga, Chlorella pyrenoidosa. The influence of pH on zeta potential (ζ) was also studied to explain the chemistry of flocculation process. The maximum harvesting efficiency (99%) was obtained with alum with deformities in algal cell surfaces. Waste egg-shell material is developed as a low-cost bio-flocculant for harvesting of Chlorella pyrenoidosa using 100 mg egg-shell bio-flocculant/L and 100 mg LACC/L, zeta potential analysis was completed to further understand the chemistry of harvesting efficiency over the different ranges of pH (2.0, 4.0, 6.0, 8.0, and 10.0). The optimized range for harvesting efficiency (HE) of pH is 4.0–8.0 for both flocculants. Maximal harvesting efficiency was achieved at pH 4.0 (99%) and pH 8.0 (95%) with bio-flocculant and LACC respectively. Hence, bio-flocculant based harvesting method is found as the best way to dewatering the algal biomass from aqueous medium with entire and intact algal cell surface with environment friendly and cost-effective approach.

Open sewage contaminated channel wastewater (OSCCW) has high pollutant loads, responsible for eutrophication, when mixed with various channels of urban communities. But, these pollutants can be converted and recovered into useful end products with the help of algal species. In this study, two species of Chlorella (C. vulgaris and C. pyrenoidosa) were selected and investigated for the production of algal biomass and nutrient removal efficiencies with 50% concentration of OSCCW, in a comparative way at lab-scale. Chlorella sp. cultivated in OSCCW have removed nitrate (76.9-78.8%) and phosphate (67.6-79.7%) whereas COD (72.4-76.2%) and BOD (62.3-72.4%) respectively. Correlation analysis was investigated between physico-chemical parameters and biochemical profile of both species to analyze the positive and negative correlation between two variables. The bio-chemical profile and biomass productivity of both species of Chlorella were observed well on the basis of productivity of biomass (60.1, 56.5 mg/l/d), carbohydrate (15.71, 8.82 mg/l/d), protein (11.21, 15.82 mg/l/d), lipid (20.8, 17.5 mg/l/d) and chlorophyll (0.78, 0.67 mg/l/d) in OSCCW. The maximum lipid content (34.6%) was obtained with C. pyrenoidosa as compared to C. vulgaris. Findings also support that OSCCW is well-off with nutrient resources, which can be suitable alternative for algal biomass production and remediated wastewater can be used for animal and fish farming type activities.

This article offers a trend of inventions and implementations of photocatalysis process, desalination technologies and solar disinfection techniques adapted particularly for treatment of industrial and domestic wastewater. Photocatalysis treatment of wastewater using solar energy is a promising renewable solution to reduce stresses on global water crisis. Rendering to the United Nation Environment Programme, 1/3 of world population live in water-stressed countries, while by 2025 about 2/3 of world population will face water scarcity. Major pollutants exhibited from numerous sources are critically discussed with focus on potential environmental impacts & hazards. Treatment of wastewater by photocatalysis technique, solar thermal electrochemical process, solar desalination of brackish water and solar advanced oxidation process have been presented and systematically analysed with challenges. Both heterogenous and homogenous photocatalysis techniques employed for wastewater treatment are critically reviewed. For treating domestic wastewater, solar desalination technologies adopted for purifying brackish water into potable water is presented along with key challenges and remedies. Advanced oxidation process using solar energy for degradation of organic pollutant is an important technique to be reviewed due to their effectiveness in wastewater treatment process. Present article focused on three key issues i.e. major pollutants, wastewater treatment techniques and environmental benefits of using solar power for removal of pollutants. The review also provides close ideas on further research needs and major concerns. Drawbacks associated with conventional wastewater treatment options and direct solar energy-based wastewater treatment with energy storage systems to make it convenient during day and night both listed. Although, energy storage systems increase the overall cost of the wastewater treatment plant it also increases the overall efficiency of the system on environmental cost. Cost-efficient wastewater treatment methods using solar power would significantly ensure effective water source utilization, thereby contributing towards sustainable development goals.

Graphical abstract The outbreak of COVID-19 pandemic has created havoc all across the globe causing exponential casualties and tremendous health and economic loss. With increasing COVID-19 cases, the amount of biomedical waste has increased manifolds making more people vulnerable to the pandemic. The developing and underdeveloped countries are already facing the challenges of waste management, and the waste generated during the pandemic scenario has added to the already existing challenges. The improper waste management practices need to be corrected; otherwise, the world will be facing a new disaster that could be termed as ‘waste disaster’. The increase in COVID-19-associated waste (CAW) quantity and their availability in the environment will result in their easy approach to other organisms, which will possibly increase the potential risk of food chain contamination. Some of the countries have already started to make backup plans and are struggling to overcome the ‘waste disaster’. In light of the limited knowledge available on the mutational properties and possible hosts of this newly emerged COVID-19, there is a great demand to have an efficient strategy to prevent the environment from further contamination in India. The necessity of the prevailing time is to create a more efficient, automatic, mechanized, and well-modified waste management system for handling the present situation and delaying the projected waste disaster in the near future in the era of COVID-19. The article aims to address the issues that originated from waste discharges, their potential sources along with possible sustainable solutions. Supplementary Information The online version contains supplementary material available at 10.1007/s11356-021-15028-5.

Water hyacinth is a rapidly growing troublesome aquatic weed plant, which causes eutrophication in water bodies and irreversible damage to the ecological system. In this work, we have investigated the water hyacinth biomass (WHB) hydrolysis efficacy of dilute alkaline (DA) pretreatment followed by biological pretreatment with white-rot fungus Alternaria alternata strain AKJK-2. The effectiveness of the dilute alkaline (DA) and biological pretreatment process on WHB was confirmed by using X-ray Diffraction (XRD) and Fourier Transform Infrared Spectrophotometer (FTIR), and was further visualized by Scanning Electron Microscope (SEM) and Confocal Laser Scanning Microscopy (CLSM). XRD spectra showed the increase in the crystallinity of pretreated samples, attributed to the elimination of amorphous components as lignin and hemicellulose. FTIR peak analysis of pre-treated WHB showed substantial changes in the absorption of cellulose functional groups and the elimination of lignin signals. Scanning electron microscopy (SEM) images showed firm, compact, highly ordered, and rigid fibril structures without degradation in the untreated WHB sample, while the pretreated samples exhibited loose, dispersed, and distorted structures. XRD indices (Segal, Landis, and Faneite), and FTIR indices [Hydrogen bond intensity (HBI), Total crystallinity index (TCI), and Lateral order crystallinity (LOI)] results were similar to the aforementioned results, and also showed an increase in the crystallinity both in alkaline and biological pretreatments. Alkaline pretreated WHB, with these indices, also showed the highest crystallinity and a crystalline allomorphs mixture of cellulose I (native) and cellulose II. These results were further validated by the CLSM, wherein fluorescent signals were lost after the pretreatment of WHB over control. Overall, these findings showed the significant potential of integrated assessment tools with chemical and biological pretreatment for large-scale utilization and bioconversion of this potential aquatic weed for bioenergy production.

Petroleum refining operations such as hydroprocessing and fluid catalytic cracking (FCC) generate huge quantities of spent catalysts containing toxic and valuable metals (Ni, V, Mo, Co, W, Al, etc.), the management of which is a serious environmental issue. Besides environmental concerns, the different metals present in the spent catalysts are also a valuable commodity to modern industries. Therefore, these spent catalysts also provide an opportunity to use it as a source of value to the refiners. In recent years, a biotechnological based leaching process 'bioleaching' has emerged as a promising eco-friendly technique for the extraction of metals from these refinery spent catalysts. Among various bioleaching agents such as archean, bacterial, or fungi, the process mediated by the fungi (Aspergillus niger, Penicillium simplicissimum, and many others) is gaining attention owing to the high metal extraction ability of the various fungal produced metabolites (organic acids) under moderately acidic conditions. Furthermore, the ability of these fungi to withstand wide process conditions (pH, spent catalyst concentration, substrate types, etc.), high metal toxicity and use of low-cost organic substrate make them an ideal candidate for bioleaching. In this review article, we shed light on the role and mechanisms of fungi involved in extracting different metals from spent hydroprocessing and FCC catalysts. Key process parameters that affect the efficiency of fungal based bioleaching are discussed. The techno-economic challenges associated with the process are elaborated, and the needed future research directions to promote its commercial applications are highlighted. Based on our analysis, it can be argued that the fungi bioleaching has potential, however, some challenges (slower kinetics, and health and safety) should be addressed before the process can be scaled up for the commercial application.

The present study evaluates the performance of a newly developed improved metal chulha (IMC) over available traditional mud chulha (TMC) as an energy-efficient nonsmoking cooking appliance for the rural households. An extensive survey of 90 respondents revealed that majority of the households use firewood for cooking in energy-inefficient TMCs. The TMC emitted considerable amount of toxic component, which can adversely affect the human health on direct exposure. To overcome this problem, we have developed an IMC, which significantly reduces energy loss and cooking time compared to TMC. In this study, we have measured the level of airborne pollutants emitted from fuelwood used for cooking purpose. In addition to this, we have also studied the thermal efficiency of IMC over TMC. A major reduction in indoor pollutants viz. PM10 (45%), PM2.5 (73%), CO (51%), SOX (22%), NOX (36%) was recorded for IMC over the TMC. The water boiling test also indicates higher thermal efficiency during all the three phases: cold start (37%), hot start (41%) and simmering test (46%) for IMC over TMC. The fuel consumption rate (g min−1) was recorded 23, 16.6, 14 and 32.2, 25.1 and 20.6 for IMC and TMC, respectively. Compared with TMC, the IMC reduced specific fuelwood consumption, increased efficiencies and lower emissions of pollutants including PM10, PM2.5, NOX, SOX and CO. A social survey in the form of a questionnaire revealed that majority of households realized that IMC will be better than the TMC in terms of handling, reduced emissions, easier cooking and efficiency.

In the present study, influence of temperature and dairy industry waste water (DIWW) concentration on the growth of Chlorella pyrenoidosa has been done along with the thermodynamic analysis of different functions viz. change in enthalpy (∆H), change in entropy (∆S), free energy change (∆G), and activation energy (E(a)) to study the impact on cell size distribution and morphological changes. Among the studied temperatures, higher biomass productivity was observed at 35 °C at 75% of DIWW. Thermodynamic analysis showed the spontaneous and exothermic nature of growth of C. pyrenoidosa. Experimental data have significantly proven the kinetic and thermodynamics functions with 35 °C temperature, ∆H (− 46.78 kJ mol(−1)), ∆S (− 0.10 kJ mol(−1)), ∆G (− 14.8 kJ mol(-1)), and E(a) (49.28 kJ mol(−1)). At this temperature, size distribution showed maximum percentage (48%) cells were of 6540 nm, whereas the minimum percentage (3%) cells were of 2750 nm. SEM–EDX study revealed that increase in temperature leads to increase in roughness and elemental deposition of metal on cell surface.

Multidrug-resistant pathogens causing nosocomial and community acquired infections delineate a significant threat to public health. It had urged to identify new antimicrobials and thus, generated interest in studying macrocyclic metal complex, which has been studied in the past for their antimicrobial activity. Hence, in the present study, we have evaluated the antimicrobial activity of the hexadentated macrocyclic complex of copper (II) (Cu Complex) derived from thiosemicarbazide against Gram-positive and Gram-negative bacteria. We observed increased susceptibility against standard isolates of Staphylococcus aureus with a minimum inhibitory concentration (MIC) range of 6.25 to 12.5 μg/mL. Similar activity was also observed towards methicillin resistant and sensitive clinical isolates of S. aureus from human (n = 20) and animal (n = 20) infections. The compound has rapid bactericidal activity, and we did not observe any resistant mutant of S. aureus. The compound also exhibited antibiofilm activity and was able to disrupt pre-formed biofilms. Cu complex showed increased susceptibility towards intracellular S. aureus and was able to reduce more than 95% of the bacterial load at 10 μg/mL. Overall, our results suggest that Cu complex with its potent anti-microbial and anti-biofilm activity can be used to treat MRSA infections and evaluated further clinically.

The present study investigate fuel wood characteristics on the basis of fuel wood value index (FVI), a proximate and ultimate analysis of 12 subtropical tree species of rural areas of Uttar Pradesh in northern India, to sort out the tree species commonly used by the rural communities and examine their energy properties. The FVI was determined on the basis of calorific value (CV), bulk density (BD), and ash content (AC). The highest CV (22.56 MJ/kg) and BD (0.80 g/cm3) were found in Prosopis juliflora, and the lowest CV (17.32 MJ/kg) and BD (0.32 g/cm3) were found in Streblus asper. The AC was found maximum in Pithecellobium dulce (2.81%) and minimum in S. asper (0.83%). Moisture content was ranged between 38.70 and 58.67%. Investigation of elemental composition in fuel wood revealed that carbon, nitrogen, hydrogen (CHN), and sulfur value ranged from 40 to 46% C, 4.80 to 6.80% H, 0.03 to 1.40% N, and sulfur was defected only in some species and its maximum value (0.012) was found in species of Tectona grandis, T. arjuna, and Ficus benghalensis. This study revealed that only the single basic parameter is not sufficient for identifying the suitable tree species for fuel wood. On the basis of FVI and other fuel wood properties species, P. juliflora, T. grandis, F. benghalensis, Alstonia scholaris, and Holopetelea integrifolia are the most preferred fuel wood species among the 12 trees studied. To enable choice of plant species for future energy plantation program may help the local people to take maximum benefit to be used as bioenergy if electricity and alternative energy sources are not available in such remote areas.

Particulate matter (PM) deposition on leaves adversely affects physical, chemical and biological nature of agricultural crops resulting in their loss of productivity and yield. Wheat being a staple food in major parts of Northern India and around the World, has been selected for research purpose by designing a study to explore the probable effects of PM deposition on wheat leaves and wheat crops to ensure the food security. PM5 (Particulate matter with aerodynamic diameter 1.20–1.40) and CIR (>0.70–0.80) for both PM5 and leaf_DDPM were observed. The size distribution of individual particles for both PM5(#194 particles) and Leaf_DDPM(#657 particles) revealed that Surface Equivalent Radius (SER) and Volume Equivalent Radius (VER) of particles observed to be 0.40–0.80 μm while surface area to be 0–1 μm2. These particles may easily block stomatal openings (with typical diameter range: 42–51 μm) of wheat leaves and damage internal leaf tissues while particle VER determines the interaction of incoming solar radiation with leaf surfaces. Average PM5 concentrations ± Standard deviations (μg/m3) were reported to be 231.05 ± 113.03. The XRF (X-Ray Fluorescence) spectrometer analysis of bulk PM5 revealed the concentrations of non-carbonaceous elements (μg/m3) as N (67.34 ± 16.09), Si (27.44 ± 11.01), Al (7.79 ± 3.37), S (3.88 ± 2.24), Na (2.29 ± 0.94), Mg (1.65 ± 0.62), K (0.51 ± 0.26), Ca (0.60 ± 0.26), Fe (0.54 ± 0.26), Cr (1.10 ± 0.70), Zn (0.05 ± 0.03), P (0.10 ± 0.03), Cu (0.07 ± 0.06). The dominant elemental oxides were calculated as SiO2, Al2O3, SO 4 2 − , Na2O, MgO, K2O, CaO, Fe2O3, Cr2O3, ZnO, P2O5, Cu2O with variable concentrations. In high humid conditions, with relative humidity (~85%) during the vegetative and flowering growth stages of wheat crops, presence of C and S rich acidic and hygroscopic particles may cause the corrosion of wheat leaves that ultimately affect the wheat crops.