Thermodynamics and Kinetics Parameters of Eichhornia crassipes Biomass for Bioenergy.

BACKGROUND: Eichhornia crassipes is an aquatic plant well known for its role in soil reclamation due to the containment of valuable nutrients. Moreover, its biomass is an abundant and low-cost biological resource. Pyrolysis of a biomass offers one of the cleanest methods to harness the bioenergy stored in the biomass. OBJECTIVE: The present study was focused on evaluating the bioenergy potential of Eichhornia crassipes via pyrolysis. METHODS: Biomass of E. crassipes was collected from a municipal wastewater pond. Oven dried powdered biomass of E. crassipes was subjected to pyrolysis at three heating rates including 10, 30 and 50 °C min-1 in a simultaneous Thermogravimetry-Differential Scanning Calorimetry analyzer under an inert environment containing nitrogen. Data obtained were subjected to isoconversional models of Kissenger-Akahira-Sunose (KSA) and Flynn-Wall-Ozawa (FWO) to understand the reaction chemistry. RESULTS: Kinetic parameters have shown that the pyrolysis followed first-order reaction kinetics. The average values of activation energies (129.71-133.03 kJ mol-1) and thermodynamic parameters including high heating values (18.12 MJ kg-1), Gibb's free energies (171-180 kJ mol-1) and enthalpy of reaction (124-127 kJ mol-1) have shown the remarkable bioenergy potential of this biomass. CONCLUSION: This low-cost biomass may be used to produce liquids, gases, and biochar in a costefficient and environmentally friendly way via pyrolysis or co-pyrolysis in the future.

Heterologous Synthesis and Recovery of Advanced Biofuels from Bacterial Cell Factories.

BACKGROUND: Microbial engineering to produce advanced biofuels is currently the most encouraging approach in renewable energy. Heterologous synthesis of biofuels and other useful industrial chemicals using bacterial cell factories has radically diverted the attentions from the native synthesis of these compounds. However, recovery of biofuels from the media and cellular toxicity are the main hindrances to successful commercialization of advanced biofuels. Therefore, membrane transporter engineering is gaining increasing attentions from all over the world. OBJECTIVE: The main objective of this review is to explore the ways to increase the microbial production of biofuels by counteracting the cellular toxicity and facilitating their easier recovery from media. CONCLUSION: Microbial synthesis of industrially viable compounds such as biofuels has been increased due to genomic revolution. Moreover, advancements in protein engineering, gene regulation, pathway portability, metabolic engineering and synthetic biology led the focus towards the development of robust and cost-effective systems for biofuel production. The most convenient way to combat cellular toxicity and to secrete biofuels is the use of membrane transport system. The use of membrane transporters is currently a serious oversight as do not involve chemical changes and contribute greatly to efflux biofuels in extracellular milieu. However, overexpression of transport systems can also be detrimental to cell, so, in future, structure-based engineering of transporters can be employed to evaluate optimum expression range, to increase biofuel specificity and transport rate through structural studies of biofuel molecules.

Pyrolysis and kinetic analyses of Camel grass (Cymbopogon schoenanthus) for bioenergy.

The aim of this work was to study the thermal degradation of grass (Cymbopogon schoenanthus) under an inert environment at three heating rates, including 10, 30, and 50°Cmin-1 in order to evaluate its bioenergy potential. Pyrolysis experiments were performed in a simultaneous Thermogravimetry-Differential Scanning Calorimetry analyzer. Thermal data were used to analyze kinetic parameters through isoconversional models of Flynn-Wall-Ozawa (FWO) and Kissenger-Akahira-Sunose (KSA) methods. The pre-exponential factors values have shown the reaction to follow first order kinetics. Activation energy values were shown to be 84-193 and 96-192kJmol-1 as calculated by KSA and FWO methods, respectively. Differences between activation energy and enthalpy of reaction values (∼5 to 6kJmol-1) showed product formation is favorable. The Gibb's free energy (173-177kJmol-1) and High Heating Value (15.00MJkg-1) have shown the considerable bioenergy potential of this low-cost biomass.