Rapid immobilization of viable Bacillus pseudomycoides in polyvinyl alcohol/glutaraldehyde hydrogel for biological treatment of municipal wastewater

A new approach for easy synthesis of Bacillus pseudomycoides immobilized polyvinyl alcohol (PVA)/glutaraldehyde (GA) hydrogel for application in a wastewater treatment system is reported. Optimization studies revealed that GA/PVA mass ratio of 0.03 and acidic pH of 2 were required for hydrogel synthesis and eventually for bacterial cell immobilization. The synthesized crosslinked matrix possessed a pore size suitable for microbial cell entrapment while maintaining cell accessibility to external environment for bioremediation. Possible crosslinking and bacterial cell immobilization in the hydrogel were evidenced by FTIR, XRD, and SEM studies, respectively. Further, the extent of crosslinking of GA with PVA was investigated and confirmed by transmittance and permeability experiments. The viability and proliferation of hydrogel embedded cells (after 25 days) was confirmed by confocal fluorescence microscopy which also indicated that acidic pH of polymer solution did not affect the immobilized live cells. B. pseudomycoides immobilized hydrogel were demonstrated to be effective for treatment of municipal wastewater and reduced biochemical oxygen demand (BOD), chemical oxygen demand (COD), and protein content below the recommended levels. Overall, the results from this bench-scale work show that employing bacteria-embedded PVA/GA hydrogel for the treatment of municipal wastewater yield promising results which should be further explored in pilot/field-scale studies.

     

海水淡化反渗透系统中膜生物污染控制的研究进展

海水反渗透膜生物污染是由微生物在膜表面沉积和生长而形成的生物膜造成的污染,因此控制膜生物污染可从杀死微生物和抑制其生长两方面进行。目前常用的控制膜生物污染的两大方法是通过投加杀菌剂(如氯、二氧化氯、臭氧、UV、DBNPA)来杀死微生物和去除碳营养元素来抑制其繁殖。应用"在线混凝+MF/UF"的预处理方法,通过去除磷来控制海水反渗透膜生物污染将成为未来的研究趋势。     

Biodegradation of Poly(ε-caprolactone) (PCL) Film by <Emphasis Type="Italic">Alcaligenes faecalis</Emphasis>

The biodegradation behavior of PCL film with high molecular weight (80,000 Da) in presence of bacterium Alcaligenes faecalis and the analysis of degraded polymer film have been carried out. Thin Films of PCL were prepared by means of solution casting method and the bacterial degradation behavior was carried in basal medium, in presence of bacteria with time variation after UV treatment. It was observed that after UV treatment the degradation of polymer film was increased and the degradation rate followed a three steps degradation mechanism. The degraded polymer film was analyzed by means of Differential Scanning Calorimeter (DSC), Thermo Gravimetric Analyzer (TGA) and Fourier Transform Infrared Spectroscope (FTIR). DSC results revealed that at the initial stages of the degradation up to 15–20 days, the bacterium preferentially degrades the amorphous parts of the polymer film over the crystalline zone. Thermo gravimetric analysis highlighted the low temperature stability of degraded films with extent of degradation. FTIR results showed the chain scission mechanism of the polymer chains and also supported the preferential degradation of amorphous phase over crystalline phase in the initial stages of the degradation.     

How sustainable are forestry clean development mechanism projects?—A review of the selected projects from India

This paper analyses social, economic and ecological issues affecting sustainability of the four selected forestry clean development mechanism (CDM) projects from India. Data from the group discussions and stakeholder interviews suggest that three out of the four projects are economically unsustainable for local people because of high opportunity cost of land and labour, and delayed and low benefits. The average opportunity cost of the land is 20000, 12000 and 9000 INR/ha/year in case of Haryana, Himachal Pradesh and Tamil Nadu, India projects respectively, which is unlikely to be met through projected carbon revenues and other benefits. A significant number of farmers have already withdrawn their private lands in Haryana and Tamil Nadu projects. Very few of them have undertaken plantations on the private lands in the Himachal project. All the four projects have undertaken block plantations of predominantly fast growing species such as Eucalyptus (Eucalyptus hybrid), Casuarina (Casuarina equisettifolia) and Ailanthus (Ailanthus excelsa) for high growth and quick returns, which could have adverse social and ecological impacts over long term. There are social and institutional issues such as low participation of local communities, weak or non existing community institutions, inflexible design and rigid CDM rules, which affect sustainability of these projects. It has implications for other carbon forestry programmes such as Green India Mission and Reducing Emissions from Deforestation and Degradation (REDD+) being rolled out at a large scale in the country. The rationale and significance of these programmes needs to be objectively reexamined in context of the issues affecting CDM projects.     

Synthesis of 2-furyl-4-arylidene-5(4H)-oxazolones as new potent antibacterial agents against phyto-pathogenic and nitrifying bacteria

Crop losses due to bacterial pathogens are a major global concern. Most of the available pesticides for these pathogens suffer from various drawbacks such as complicated synthesis, high cost, high toxicity, pesticide resistance and environmental hazards. To overcome these drawbacks, the present study was undertaken to find a potent bactericide. Therefore, a series of compounds comprising bioactive furyl and oxazolone rings was synthesized under microwave irradiation and screened for in vitro antibacterial activity. The reactions were completed in fewer than 2 minutes with minimal use of solvents and resulted in high yields. These compounds were screened for antibacterial activity against plant pathogens, Xanthomonas oryzae, Ralstonia solanacearum and nitrifying bacteria, Nitrosomonas species under laboratory conditions. Five compounds were active as antibacterial agents against Xanthomonas oryzae and Ralstonia solanacearum. However, all compounds were effective against the Nitrosomonas species and the best one was 2-furyl-4-(3-methoxy-4-hydroxybenzylidene)-5(4H)-oxazolone. The study revealed the fast and environmentally friendly synthesis of bioactive title compounds, which also hold promise to be used as prototypes for the discovery of potent analogues.     

Agricultural innovation and adaptation to climate change: empirical evidence from diverse agro-ecologies in South Asia

While impacts of climate change on agricultural systems have been widely researched, there is still limited understanding of what agricultural innovations have evolved over time in response to both climatic and non-climatic drivers. Although there has been some progress in formulating national adaptation policies and strategic planning in different countries of South Asia, research to identify local-level adaptive strategies and practices is still limited. Through eight case studies and a survey of 300 households in 15 locations in India, Nepal and Bangladesh, this paper generates empirical evidence on emerging agricultural innovations in contrasting socio-economic, geographical and agro-ecological contexts. The study demonstrates that several farm practices (innovations) have emerged in response to multiple drivers over time, with various forms of institutional and policy support, including incentives to reduce risks in the adoption of innovative practice. It further shows that there is still limited attempt to systematically mainstream adaptation innovations into local, regional and national government structures, policies and planning processes. The paper shows that the process of farm-level adaptation through innovation adoption forms an important avenue for agricultural adaptation in South Asia. A key implication of this finding is that there is a need for stronger collaborations between research institutions, extension systems, civil society and the private sector actors to enhance emerging adaptive innovations at the farm level.     

Economic liabilities of environmental pollution by coal mining: Indian scenario

India is the first country to introduce environmental legislation in the constitution but because of lengthy legal procedures, it is very difficult to control environmental deterioration. There are many factors responsible for this deterioration. Coal mining is one such activity where deterioration is very severe and the present communication aims this aspect. Coal is the one of the most essential mineral having large reserves in India. It’s mining and beneficiation produce a variety of pollutants. The main pollutants emitted during the processing of coal are green house gases, coal dust and acid mine drainage. Many reports on different aspects of coal mining are available including reports on emission of different pollutants but the present work is probably only of it’s kind in which the authors have tried to determine environment liability directly in terms of economy. It was found that greenhouse liabilities, coal dust liability and sulphur liability are accounted for 12.07, 5.0 and 101.97 US$, making an overall 2.4% of the total economic gains due to coal mining. During the calculations approximate number of total workers and other parameters have been taken into consideration. Who pays for this irreversible damage is a question. Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue.     

Effects of gamma irradiation on Holcus lanatus (Yorkshire fog grass) and associated soil microorganisms

An investigation was conducted to determine the impact of acute doses of gamma radiation on the microbial community structure of a Holcus lanatus dominated grassland soil. Mesocosms containing soil and established grass were irradiated using a sealed (137)Cs source (7.0 Gy min(-1)). Doses ranged from 5 to 160 Gy, analyses were conducted on the day of irradiation, then 7 and 30 days later. Plant growth and arbuscular mycorrhizal fungal colonisation of roots were reduced by irradiation. Gram-negative bacteria, and microbial metabolic capacity were also negatively affected by treatment. Microbial biomass measured by phospholipid fatty acid (PLFA) analysis, showed an increase at doses above 20 Gy, 7 and 30 days after treatment. Proportions of Gram-positive bacterial and fungal PLFAs fluctuated inversely to each other, in response to both sampling time and radiation dose. We hypothesise that many of the observed soil microbial responses are indirect effects mediated by the influence of ionising radiation on the plants in this system.     

Hepato and nephrotoxicity in rat exposed to endosulfan

The indiscriminate and injudicious use of pesticides particularly endosulfan in agriculture and animal husbandry practices has considerably increased the risk of human health hazard. The present work was therefore undertaken to evaluate the toxic effect of endosulfan on the vital organs viz. liver and kidney of rat. Oral administration of endosulfan at the dose level of 10 mg/kg b.wt./day for two and four weeks showed toxic interference with the biochemistry and histology of rat liver and kidney. The biochemical parameters viz. Aspartate amino transferase, alanine amino transferase, acid phosphatase, alkaline phosphatase, bilirubin urea and creatinine were increased which clearly showed the hepato and nephrotoxic effect of endosulfan. Histopathologically the size of liver was increased, sinusoidal dilation, pyknotic nuclei, cytoplasmic degranulation and various nuclear aberrations were observed. Similarly pathological alterations viz. chronic glomerulonephritis, glomerulosclerosis, odenoma and glomerulus deposits were observed in the kidney.