Energy, Ecology and Environment

Thermochemical characterization of Nigerian Jatropha curcas fruit and seed residues for biofuel production Abstract This study investigates the thermochemical properties of the separate components of jatropha biomass residues of Nigerian origin towards bio-oil production. The biomass residues (Jatropha curcas fruit shells and seed coat) were obtained from their mature jatropha fruits and subjected to physico-chemical characterization (structural composition analysis, thermogravimetric analysis, proximate and ultimate analyses). The structural compositions (extractives, hemicellulose, cellulose and lignin contents) of jatropha fruit shell and jatropha seed coat were 3%, 34.0%, 40.0% and 12.7%, and 42.3%, 32.5%, 10.5% and 5.7%, respectively. The thermogravimetric analysis showed that the ash contents of jatropha seed coat and jatropha fruit shell were 0.8% and 15.4%, respectively. The carbon contents were 48.3% and 41.5%, while measured calorific values were 20.06 MJ/kg and 17.14 MJ/kg for jatropha seed coat and fruit shell, respectively. The carbon, hydrogen, nitrogen and sulphur contents were found comparable with those in the literature. This study indicated that the thermochemical properties of the Nigerian Jatropha fruit and seeds residues were comparable with literature values and residues were found suitable for bio-oil production.

Diversification of nonhydro renewable energy sources in developing countries Abstract Despite the increasing attention on renewable energy, still there is limited empirical analysis about its determinants especially in developing countries. In this paper, we investigate the determinants of diversification of nonhydro renewable energy sources such as wind, solar, geothermal, biomass and waste using an extensive data set covering more than 100 developing countries from 1980 to 2010. We explore several estimation techniques such as negative binomial regression and Poisson pseudo-maximum likelihood estimation. Controlling for time and regional variations, results show that higher per capita income, implementation of renewable energy policy, advances in technological innovation and improvement in human capital promotes diversification of nonhydro sources of renewable energy. However, financial development showed no robust evidence of its effect on the diversification. Similarly, high dependence on foreign sources of fuel, increasing world market price for crude oil and increasing population will push developing countries to diversify sources of nonhydro renewable energy. In contrast, the local abundance of hydropower, high production of fossil fuel, development aid and foreign direct investment do not contribute to diversification. Results highlight salient information in drawing the roadmap for further diffusion of renewable energy in developing countries. This suggests that policy makers should exert consistent effort in integrating renewable energy in the country’s energy mix.

Public perceptions of shale gas in the UK: framing effects and decision heuristics Abstract Using two equivalent descriptions of the shale gas development process, we asked individuals to indicate their levels of support as well as their perceptions of the risks and costs involved. In version 1, shale gas development was framed as ‘fracking’, whereas under version 2 it was framed as ‘using hydraulic pressure to extract natural gas from the ground’. We find that individuals’ support for shale gas development is much lower when using the term ‘fracking’ as opposed to the synonymous descriptive term, and moreover, these differences were substantive. Our analysis suggests that these differences appear to be largely the result of different assessments of the risks associated with ‘fracking’ as opposed to ‘using hydraulic pressure to extract natural gas from the ground’. Our proposed explanation for these differences rests on the idea that shale gas development is a technical and complex process and many individuals will be bounded by the rationality of scientific knowledge when it comes to understanding this process. In turn, individuals may be relying on simple decision heuristics shaped by the way this issue is framed by the media and other interested parties which may constrain meaningful discourse on this topic with the public. Our findings also highlight some of the potential pitfalls when it comes to relying on survey research for assessing the public’s views towards complex environmental issues.

Prioritization of prospective third-generation biofuel diatom strains Abstract Energy has been playing a pivotal role in the progress and prosperity of a nation. Growing demands with dwindling stock of fossil fuels with the associated greenhouse gas (GHG) footprint and the consequent changes in the climate during the post-industrialization era have necessitated the exploration for sustainable energy alternatives. Biofuels are gaining importance as viable alternatives to fossil fuels during the last decade. Microalgae, especially diatoms, have shown prospects to be viable third-generation biofuel feedstocks, due to its higher lipid productivity, shorter cycling time and ubiquitous presence. This investigation focuses on identifying robust diatom strains that can sustain the vagaries of nature and yield higher lipid. This would avert the imminent risks of contamination associated with pure cultures and higher costs. The current research involved inventorying diatom consortia across diverse lentic and lotic habitats of the Aghanashini estuary with varied levels of nutrients primarily influenced by distribution of flora and fauna to understand the role of environmental parameters and nutrient levels in species composition, community structure. This effort is an essential prelude to phyco-prospecting potential candidates for third-generation biofuel production. The results obtained from the present study provide insights into an optimal habitat conditions, more specifically ideal nutrient concentrations for enhanced growth of different clusters of diatoms, a determining factor for higher biomass and lipid productivity. Multivariate statistical analyses revealed an occurrence of 27 tolerant diatoms species belonging to genera’s Amphora, Cyclotella, Navicula, Nitzschia and Pleurosigma. Linkages of the dominant and productive clusters of diatoms with habitat nutrient concentrations were investigated through agglomerative hierarchical clustering. Probable empirical relationship among varying environmental conditions and corresponding lipid content of diatoms were explored through regression analyses. Investigations of species tolerant to higher nutrient loads and assessment of lipid aided in prioritizing the strains with benefits of phyco-remediation as well as prospects of biofuel.

Land use changes: a key ecological driver regulating methanotrophs abundance in upland soils Abstract Land use changes have been recognized as one of the key ecological drivers in regulation of methane (CH4) consumption from dry upland soils. This study investigated the impact of land use changes and different soil depths (0–10, 10–20 and 20–30 cm) on soil physicochemical properties and methanotrophs abundance in dry tropical region of Vindhyan uplands. Four different land use types (agriculture land, mixed forest, savanna and natural forest) were selected for a comparative study. Among the different land uses and soil depths, results indicated significantly higher soil moisture (SM), organic-C, inorganic nutrients, water holding capacity (WHC) and methanotrophs abundance at 0–10 cm depth of natural forest compared to other sites. Across different land uses, number (8.11 × 107 pmoA copies g−1 of dry soil) of methanotrophs isolated from the natural forest soil was statistically higher than the soils of other land use types. The variations in pmoA gene numbers across different land uses and soil depths were significant (P < 0.001). The pmoA gene numbers were positively correlated with soil C/N ratio (R2 = 0.9233) and moisture (R2 = 0.9675) contents. The decreasing order of pmoA gene abundance across different land uses was natural forest > mixed forest > savanna > agriculture land. The result suggest that land use changes (conversion of natural forest to agricultural land) alter the major soil properties (SM, WHC, organic matter, C/N ratio, etc.) and significantly reduce the methanotrophs and pmoA gene numbers. The land use management practices (application of bio-fertilizers in place of chemical fertilizers), especially for the degraded agricultural soils, could be beneficial option to mitigate the negative impacts on soil methanotrophs and their CH4 sink activity in the upland soil of Vindhyan region.

Biodegradation of crude oil by Halomonas elongata strain KWPA-12: a moderately halophilic strain detected in oil spills around Garo sulfidic springs, MIS Oilfield, Iran Abstract The oil spills in the vicinity of the Garo sulfidic springs in Golgir region, MIS oilfield, Iran, were investigated for halotolerant/halophilic microorganisms capable of crude oil biodegradation. Screenings resulted in an isolate capable of growth on crude oil of the local Asmari reservoir in media containing 30–100 g/L NaCl at 28 °C. The isolate, designed as KWPA-12, was an aerobic, motile, oxidase and catalase positive, Gram-negative rod. It was shown that strain KWPA-12 can utilize crude oil as the carbon and sulfur sources with a significant efficiency. The Asmari crude oil biodegradation in 90 g/L NaCl containing media was investigated by turbidity measurement, GC-FID and TPH analyses. The results showed that the aliphatic hydrocarbons including: small C11–C12 and long chains: C31–C33, are mostly favored by strain KWPA-12. Anthracene: a tri-ring and one of the most dominant poly-aromatic compounds of Asmari crude oil, was reduced down to about 1.1% of the starting moiety. Phylogenetic investigations performed on the partial 16S rRNA gene sequence indicated that the strain belongs to the genus Halomonas and it fell into the Halomonas elongata clade.

Compartive life cycle assessment of mechanized and semi-mechanized methods of potato cultivation Abstract Evaluating the environmental performance of production systems is necessary for the assessment of ecosystems from the perspective of sustainability. Life cycle assessment is a suitable method of evaluating the environmental impact of a product, process or activity by identifying, quantifying and assessing the resources expended and the emissions and waste released into the environment. The present study used life cycle assessment (LCA) of one ton of potatoes (Solanum tuberosum L.) from the boundary of a farm in Markazi province in Iran. The data were obtained from 120 questionnaires and include input sources from the cities of Arak and Shazand for semi-mechanized and traditional cultivation systems. Investigation of the environmental impact of potato cultivation was done using the LCA method and Simapro 8.0.4 software. It was estimated for abiotic depletion potential, global warming potential and ozone layer depletion potential. The results show that the semi-mechanized farming system has destructive effects on global warming (1.71 kgSbeq) and causes abiotic depletion (227.56 kgco2eq). The traditional cultivation method causes ozone layer depletion (0.00005 kgCFC-11) from diesel fuel consumption by water pumps. The strategies outlined in the alternative framework include replacement by renewable energy, ecological and agronomic pest control and optimization strategies such as development and improvement of machinery in conformity with international standards, training farmers to make optimal use of inputs and education to reduce damaging effects to the environment.

Banana peel waste management for single-cell oil production Abstract Banana peel waste was explored as a substrate for single-cell oil production using a promising oleaginous yeast Rhodotorula glutinis NRRL Y-1091 and fungus Ganoderma wiiroense under solid-state versus submerged fermentation for 8 days. Higher productivity and yield of lipids of 0.020 g lipid/g starch was recorded in both types of fermentation, with the fungal isolate G. wiiroense as compared to R. glutinis. Amylase, β glucosidase and inulinase activity were also monitored, which followed a similar trend, with highest values on 6th or 8th day of incubation. Lipase activity was not detected in the crude extract of both strains. Inulinase activity was highest at 8th day incubation in submerged fermentation with the fungal isolate G. wiiroense. FAME analyses revealed that the composition of the lipids had promising potential as good-quality biodiesel. The high levels of inulinase activity in the yeast and fungal strains enhanced the production of monomeric sugars from inulin present in banana peel, which, in turn, facilitated greater conversion to lipids and stimulated bio-oil production.

Assessing bioethanol extraction potential from waste pulps of cassava ( Manihot esculenta Crantz) via aerobic fermentation Abstract The advocacy of producing biofuels from wastes would answer the call for energy and environmental sustainability. This call is very timely considering the issues of global warming, increasing greenhouse gas emissions, diminishing natural resources, and enlarging human population. For one, the increasing generation of waste pulps from the growing numbers of starch-producing industries using cassava (Manihot esculenta Crantz) has become alarming because the improper disposal of these causes putrefaction odor, leachate contamination on water bodies, illnesses/diseases of community residents, and so on. In this work, the potential of cassava waste pulps (CWP) from starch industry was assessed with regard to the extraction of bioethanol via aerobic fermentation. The effect of yeast loading (0–4 tsp) and mashing duration (3–11 min) was evaluated on their influence on the bioethanol yield in CWP fermentation through central composite design of the response surface methodology. The result showed that 5.93 ± 0.03 mL of bioethanol could be extracted from a kilogram of fresh CWP after 7-day aerobic fermentation at conditions of 7 min mashing duration (42 °C) and 1 tsp yeast loading. Yeast loading and mashing duration are both significant with regard to bioethanol production. The gas chromatography analysis revealed 0.08% v/v bioethanol in the fermentation broth.

Effects of biomass types on the co-pyrolysis behaviour of a sub-bituminous high-sulphur coal Abstract This communication reports the thermo-kinetic behaviours of three different types of biomass samples and their blends with a sub-bituminous high-sulphur coal. Physicochemical properties were evaluated by various fuel characterization methodologies as well as instrumental methods such as thermal (TG/DTG) analysis, Fourier transforms infrared (FTIR) spectrophotometry, scanning electron microscopic (SEM) technique. Thermo-kinetic parameters of various samples were also evaluated by using Coats and Redfern method. Results indicate that the pyrolytic thermal decomposition behaviours of woody biomass samples are quite different from plant leaf-based biomass sample due to the differences in the chemical compositions. Similarly, thermo-kinetic behaviours of coal-biomass blends are significantly different from the pure coal and pure biomass samples. The lowering of reaction order and activation energy of coal decomposition with increasing biomass contents in the blend can be related with the increasing biomass-based volatile matter content in the blends as well as the catalytic effect of biomass-based alkali and alkaline metal enriched biochar. On the other hand, catalytic effect of coal on the pyrolytic biomass decomposition is only observed at higher biomass replacement level. Analyses of the results obtained from calorific value and apparent activation energy reveal the presence of synergistic effects during the combustion of coal-biomass blend in calorimeter as well as the thermal decomposition of blend under nitrogen atmosphere.