A critical review on global trends in biogas scenario with its up-gradation techniques for fuel cell and future perspectives

Renewable biogas production technology is an excellent method for eradication of greenhouse gas emission and thereby reducing global warming. This review discusses extensively on global biomass potential, energy need and method of satisfying the energy demand through sustainable techniques. One of the best alternative technological developments for the conversion of waste into useful energy is anaerobic digestion to produce biogas. It is recognized as one among leading green energy to manage the environmental and meet the current energy tasks to tackle globally. Generally, biogas can be utilized for cooking, heat and electricity generation. In order to extend the scope of application, traces of carbon dioxide, hydrogen sulphide has to be removed by several upgrading technologies to produce high purity methane (90%). This study discusses on biogas up-gradation using physical and chemical absorption, membrane separation, cryogenic separation, hybrid technology etc. Among the various up-gradation techniques, hybrid technology yields methane purity of 97%. In addition, this work reviews about benefits and problems in anaerobic integrated Solid Oxide Fuel Cell (SOFC) with latest real-world achievement in SOFC. Several SOFC systems with dynamic model development were reviewed based on efficiency of power generation. SOFC generates 45% more electricity than generator with heat engine. This review extends the scope for further research in biogas upgradation and global warming mitigation potential with carbon credits.     

The Effect of 1-Methylcyclopropene (1-MCP) on Quality and Cell Wall Hydrolases Activities of Fresh-Cut Muskmelon (Cucumis melo var reticulatus L.) During Storage

The effects of 1-methylcyclopropene (1-MCP) on quality and cell wall hydrolases activities changes in fresh-cut muskmelon fruit stored at 4?±?1 °C for 7 days were investigated. The results showed that ethylene production of the fresh-cut fruit remained constant during refrigerated storage. 1-MCP treatments delayed the loss of fresh weight and the increase in electrolyte leakage and maintained the firmness of the fresh-cut fruit. The best results are showed in the fresh-cut fruit treated with 1.0 μL L^?1 1-MCP. The use of 1-MCP had no influence on the total soluble solids (TSS) content and pH of the fresh-cut fruit which they remained constant over storage. The titratable acidity (TA) of the fresh-cut fruit decreased during storage and the sample treated with 1.0 μL L^?1 1-MCP showed the lowest data. TSS/TA ratio increased during storage and the TSS/TA ratio was lower in 1-MCP-treated samples than that for the control one. The use of 1-MCP inhibited polygalacturonase (PG), β-galactosidase (β-Gal) and β-galactanase activities, whereas the increases in these enzymes activities were found in the control. Antioxidant capacity and total phenolics content of both 1-MCP-treated and untreated samples remained constant over storage. The reduction of total ascorbic acid content was detected after 7 days of storage. The ascorbic acid content in 1-MCP-treated sample was slightly higher, although not significantly different, than that of the control after 7 days. These results suggest that the loss of firmness was the key factor affecting quality of fresh-cut muskmelon fruit and the use of 1-MCP maintained the quality and inhibited the loss of firmness by retarding the increase in electrolyte leakage and inhibiting cell wall hydrolases activities.