Technical options for optimization of production of Jatropha as a biofuel feedstock in arid and semi-arid areas of Zimbabwe

Biofuels are being promoted as sustainable alternatives to fossil fuels both from energy supply perspective as well as a technical option to respond to climate change. Various crops are grown throughout the world to supply feedstocks for the production of biofuels. In sub-Saharan Africa, Jatropha curcas is considered to be the most suitable feedstock for production of biodiesel. Zimbabwe is a tropical country with suitable growth conditions for Jatropha. Since 2005, the production of Jatropha has gathered momentum in the country. The plan for production of Jatropha has concentrated on boosting production areas. Not much attention has been given to technical issues that are important in optimizing the yield and quality norms of Jatropha seed. This paper discusses technical interventions at two levels of the value chain that are required to optimize production of Jatropha in the country as a commercially viable energy crop. Emphasis is placed on the need to supply elite planting materials to optimize seed yield and seed quality as well as consider suitable agro-techniques required to establish the Jatropha plantations. Given that the longevity of Jatropha trees is 50 years, the objective is to establish plantations based on improved germplasm rather than rely on wild type germplasm.     

Life cycle assessment of Jatropha biodiesel as transportation fuel in rural India

Since 2003 India has been actively promoting the cultivation of Jatropha on unproductive and degraded lands (wastelands) for the production of biodiesel suitable as transportation fuel. In this paper the life cycle energy balance, global warming potential, acidification potential, eutrophication potential and land use impact on ecosystem quality is evaluated for a small scale, low-input Jatropha biodiesel system established on wasteland in rural India. In addition to the life cycle assessment of the case at hand, the environmental performance of the same system expanded with a biogas installation digesting seed cake was quantified. The environmental impacts were compared to the life cycle impacts of a fossil fuel reference system delivering the same amount of products and functions as the Jatropha biodiesel system under research. The results show that the production and use of Jatropha biodiesel triggers an 82% decrease in non-renewable energy requirement (Net Energy Ratio, NER = 1.85) and a 55% reduction in global warming potential (GWP) compared to the reference fossil-fuel based system. However, there is an increase in acidification (49%) and eutrophication (430%) from the Jatropha system relative to the reference case. Although adding biogas production to the system boosts the energy efficiency of the system (NER = 3.40), the GWP reduction would not increase (51%) due to additional CH₄ emissions. For the land use impact, Jatropha improved the structural ecosystem quality when planted on wasteland, but reduced the functional ecosystem quality. Fertilizer application (mainly N) is an important contributor to most negative impact categories. Optimizing fertilization, agronomic practices and genetics are the major system improvement options.     

Impact assessment of fruit predation by Scutellera perplexa Westwood on the reproductive allocation of Jatropha

Present study focused on the fruit feeding behavior of insect predator Scutellera perplexa Westwood, its impact and degree of injury to the developing fruits and seeds of Jatropha. The study revealed that S. perplexa was synchronized with the phenology of Jatropha and responded when fruits were available. The predator completed its life cycle exclusively on Jatropha curcas and caused severe damage to developing fruit by sap sucking, consequently led to premature fruit abortion, significant reduction in fruit and seed size and subsequent yield. Fruit feeding also caused dark ‘patch’ formation on the pericarp, which hampered seed development and initiated premature rupturing of pericarp.     

Determinants and extent of land allocation for Jatropha curcas L. cultivation among smallholder farmers in Malawi

This study analysed factors that influence household’s decision to plant Jatropha curcas and the extent of land conversion to J. curcas. Results indicate that age, education of household head, availability of labour and ownership of uncultivated land have a positive influence on land allocation to J. curcas whereas ownership of livestock and non-farm income deterred households from cultivating the crop. This suggests that poor households with no off-farm income are more likely to adopt J. curcas than richer households with livestock and income from non-farm activities. In general, the results suggest that individual and household characteristics are important determinants of decision to plant J. curcas and scale-up its adoption. This calls for designing appropriate strategies and regulatory frameworks to harness the potential economic opportunities from J. curcas cultivation, while protecting the environment and rural communities from the adverse effects of land alienation from the mainstream agriculture for J. curcas cultivation at the expense of traditional crops.     

Microalgae Chlorella as a potential bio-energy feedstock

Microalgae are promising biomass species owing to their fast growth rate and high CO₂ fixation ability as compared to terrestrial plants. Microalgae have long been recognized as potentially good source for biofuel production because of their high oil content and rapid biomass production. In this study Chlorella sp. MP-1 biomass was examined for its physical and chemical characteristics using Bomb calorimeter, TGDTA, CHN and FTIR. The proximate composition was calculated using standard ASTM methodology. Chlorella sp. MP-1 biomass shows low ash (5.93%), whereas high energy (18.59 MJ/kg), carbohydrate (19.46%), and lipid (28.82%) content. The algal de-oiled cake was characterized by FTIR spectroscopy and thermogravimetric study at 10 °C/min and 30 °C/min to investigate its feasibility for thermo-chemical conversion. The present investigation suggests that within the realm of biomass energy technologies the algal biomass can be used as feedstock for bio and thermo-chemical whereas the de-oiled cake for thermo-chemical conversion thereby serving the demand of second generation biofuels.     

Potential of microalgae oil from Dunaliella tertiolecta as a feedstock for biodiesel

Alternative, non-food based biomass fuel feedstock development is vital for our national security, economy and the environment. Microalgae are among the most promising of these alternatives. Microalgal cell growth rates and metabolic products are affected by a combination of environmental parameters. In this work, the influences of light source, light intensity, CO₂ concentration, and photoperiod on the growth of Dunaliella tertiolecta (D. tertiolecta) were studied. The effects of these environmental parameters on the lipid content and fatty acid composition of D. tertiolecta were also investigated. Red light-emitting diodes (LEDs), white LEDs, and fluorescent lights were all found to be effective for algal growth. Increasing light intensity resulted in significantly more rapid algal growth, and increasing the period of light also significantly increased biomass productivity. Similar growth rates were observed for 2%, 4%, and 6% CO₂-concentrations. The different light sources and intensities were found to have no significant effect on FAME composition of D. tertiolecta. Methyl linolenate and methyl palmitate were found to be the major components of FAME produced from D. tertiolecta oil. D. tertiolecta and its derived oils should be a suitable feedstock for biofuel production.     

Vegetable oil production potential from Jatropha curcas, Croton megalocarpus, Aleurites moluccana, Moringa oleifera and Pachira glabra: Assessment of renewable energy resources for bio-energy production in Africa

Research on vegetable oil for biofuels in Africa and Asia has focused mainly on Jatropha curcas while other potential oil bearing plants have received little attention. Vegetable oil production potential for five oil bearing plant species namely: Aleurites moluccana, Croton megalocarpus, Jatropha curcas, Moringa oleifera and Pachira glabra were investigated. Nuts and seeds of the plants were collected from the wild and their potential for vegetable oil production assessed in terms of seed/nut acreage yield, seed/nut oil content, harvesting requirement, and upstream processing before vegetable oil recovery. All five varieties were found to contain acceptable but different oil content ranging from 20 to 33% w/w, and seed/nut acreage yield of 3 t ha⁻¹ y⁻¹ to 12.5 t ha⁻¹ y⁻¹. Upstream processing was needed for A. moluccana to break open nuts to release the kernel, and dehulling for both C. megalocarpus and J. curcas to release the seeds, before extracting the vegetable oil, while the seeds of both M. oleifera and P. glabra did not need upstream processing. The Multi-criteria Decision Analysis ranked C. megalocarpus as the plant with the highest vegetable oil production potential of 1.8 t ha⁻¹ y⁻¹ followed by M. oleifera, J. curcas (1 t ha⁻¹ y⁻¹), A. moluccana, and P. glabra. The analysis underlines the need for more studies on C. megalocarpus and M. oleifera for biofuel production in Africa and other regions.     

Fermentative hydrogen production by Clostridium butyricum CGS5 using carbohydrate-rich microalgal biomass as feedstock

In this work, a carbohydrate-rich microalga, Chlorella vulgaris ESP6, was grown photoautotrophically to fix the CO₂. The resulting microalgal biomass was hydrolyzed by acid or alkaline/enzymatic treatment and was then used for biohydrogen production with Clostridium butyricum CGS5. The C. vulgaris biomass could be effectively hydrolyzed by acid pretreatment while similar hydrolysis efficiency was achieved by combination of alkaline pretreatment and enzymatic hydrolysis. The biomass of C. vulgaris ESP6 containing a carbohydrate content of 57% (dry weight basis) was efficiently hydrolyzed by acid treatment with 1.5% HCl, giving a reducing sugars (RS) yield of nearly 100%. C. butyricum CGS5 could utilize RS from C. vulgaris ESP6 biomass to produce hydrogen without any additional organic carbon sources. The optimal conditions for hydrogen production were 37 °C and a microalgal hydrolysate loading of 9 g RS/L with pH-controlled at 5.5. Under the optimal conditions, the cumulative H₂ production, H₂ production rate, and H₂ yield were 1476 ml/L, 246 ml/L/h, and 1.15 mol/mol RS, respectively. The results demonstrate that the C. vulgaris biomass has the potential to serve as effective feedstock for dark fermentative H₂ production.     

Resource demand implications for US algae biofuels production scale-up

Photosynthetic microalgae with the potential for high biomass and oil productivities have long been viewed as a promising class of feedstock for biofuels to displace petroleum-based transportation fuels. Algae offer the additional benefits of potentially being produced without using high-value arable land and fresh water, thereby reducing the competition for those resources between expanding biofuels production and conventional agriculture. Algae growth can also be enhanced by the use of supplemental CO₂ that could be supplied by redirecting concentrated CO₂ emissions from stationary industrial sources such as fossil-fired power plants, cement plants, fermentation industries, and others. In this way, algae may offer an effective means to capture carbon emissions for reuse in renewable fuels and co-products, while at the same time displacing fossil carbon fuels to help bring about a net reduction in overall carbon emissions. Significant displacement of petroleum fuels will require that algae feedstock production reach large volumes that will put demands on key resources. This scenario-based analysis provides a high-level assessment of land, water, CO₂ and nutrient (nitrogen, phosphorus) demands resulting from algae biofuel feedstock production reaching target levels of 10 billion gallons per year (BGY), 20 BGY, 50 BGY, and 100 BGY for four different geographical regions of the United States. Different algae productivities are assumed for each scenario region, where relative productivities are nominally based on annual average solar insolation. The projected resource demands are compared with data that provide an indication of the resource level potentially available in each of the scenario regions. The results suggest that significant resource supply challenges can be expected to emerge as regional algae biofuel production capacity approaches levels of about 10 BGY. The details depend on the geographic region, the target feedstock production volume, and the level of algae productivity that can be achieved. The implications are that the supply of CO₂, nutrients, and water, in particular, can be expected to severely limit the extent to which US production of algae biofuel can be sustainably expanded unless approaches are developed to mitigate these resource constraints in parallel to emergence of a viable algae technology. Land requirements appear to be the least restrictive, particularly in the Western half of the country where larger quantities of potentially suitable classes of land exist. Within the limited scope and assumptions of this analysis, sustainable photosynthetic microalgae biofuel feedstock production in the US in excess of about 10 BGY will likely be a challenge due to other water, CO₂ and nutrient resource limitations. Developing algae production approaches that can effectively use non-fresh water resources and minimize both water and nutrient requirements will help reduce resource constraints. Providing adequate CO₂ resources for enhanced algae production appears the biggest challenge, and could emerge as a constraint at oil production levels below 10 BGY.     

Oleaginous yeast Cryptococcus curvatus culture with dark fermentation hydrogen production effluent as feedstock for microbial lipid production

Volatile fatty acids (VFA) from dark fermentation hydrogen production were tested as carbon sources for the culture of oleaginous yeast Cryptococcus curvatus, which is a promising feedstock for biofuel production. The optimal acetate concentration and pH were investigated when potassium acetate was used as the sole carbon source. Comparisons were then made when hydrogen production effluent (HPE) from synthetic wastewater was tested as feedstock. A pH-stat culture fed with acetic acid ultimately produced 168 g/L biomass, with a lipid content of 75.0%. No inhibitor to yeast growth was produced in the hydrogen production process. However, inhibition occurred in culture with HPE from food waste (FW), indicating that inhibitors may be present in the original raw food waste. This inhibition could be avoided by a process that uses glucose as the initial carbon source and then is continuously fed with FW-HPE. The biomass productivity in this continuous culture process reached 0.34 g/L/h, but the lipid content was only 13.5%. These results suggest that FW-HPE alone is not an optimal feedstock, but HPE derived from nitrogen-deficient waste streams could be good feedstocks. This study provides preliminary evidence for the feasibility of using organic waste for the co-production of hydrogen and lipid.     

Effects of auxins and thiamine on the efficacy of techniques of clonal propagation in Jatropha curcas L.

Effect of auxins (IAA, IBA, NAA) and vitamin-B₁ (thiamine) on rooting response of branch cuttings and air-layers of Jatropha curcas in relation to spring and monsoon seasons was investigated. Spring season was found best for clonal multiplication of genetically superior material in jatropha. Cuttings treated with 600 and 800 mg L⁻¹ thiamine showed 100% sprouting in both seasons. The average sprout growth was also found maximum in thiamine treated cuttings. Auxins enhanced rooting of cuttings in spring season but showed very poor response or even failed to root during monsoon. Among different growth regulators; thiamine triggered highest rooting during monsoon and was comparable during spring season. Average percent rooting was also recorded maximum in air-layers treated with thiamine (75, 150, 300, 600 mg L⁻¹) in comparison to auxins in both the seasons. However, number of roots per layer increased with increasing concentration of NAA and IBA in spring but decreased in monsoon season. Cleft grafting was found more promising in terms of success in rainy season however; the growth of the grafted plants was quite slow as compared to spring season. This technique can be practically applied on commercial scale in the areas where Jatropha gossypifolia grows as weed.     

Correlating the phenotypic and molecular diversity in Jatropha curcas L.

Thirty four Jatropha germplasm accessions, selected based on unique phenotypic traits from 180 accessions collected from diverse geographical regions were subjected to field evaluation and molecular analysis. The field evaluation using eight quantitative traits showed significant variation among the germplasm. The molecular analysis using 56 RAPD and 40 ISSR primers resulted in 7 and 8 clusters, respectively. The accession IC541633 from Bastar (Chattisgarh) emerged as the most diverse accession. An attempt has been made to correlate the clustering based on molecular data with the quantitative traits. There was partial correlation between the quantitative traits and molecular data. Interestingly, the diverse accessions according to molecular diversity were characterized by unique phenotypes. Time of flowering, inflorescence type and number, leaf colour and texture were the traits contributing to variation. These traits may be used in identification of diverse accessions during germplasm exploration surveys or short listing of accessions for crossing in Jatropha improvement programmes.     

Morphological,physico-chemical and micropropagation studies in Jatropha curcas L. and RAPD analysis of the regenerants

Four accessions of Jatropha curcas L. were characterized with respect to their yield and physico-chemical properties of seed-oil. Further, an efficient micropropagation protocol was developed followed by RAPD analysis of the regenerants. Although the highest 1000-seed-weight and seed-oil content were recorded in OJC1 and OJC5 accessions respectively, the seed-oil of OJC9 accession was more suited for biodiesel production due to the desirable characteristics like low values of free fatty acids, acid value, moisture content and total unsaturated fatty acids. An accession – independent micropropagation protocol of Jatropha was optimized by using axillary nodal explants with MS medium supplemented with a combination of growth regulators, glutamine and citric acid. All the accessions were amenable to in vitro culture, and the highest number of plantlets could be regenerated from the OJC5 accession. Although no somaclonal variation was recorded in the regenerants of all the accessions, RAPD analysis confirmed their genetic similarity and also the similarity of the clones with their respective mother plants.     

Land use and second-generation biofuel feedstocks: The unconsidered impacts of Jatropha biodiesel in Rajasthan,India

Governments around the world see biofuels as a common solution to the multiple policy challenges posed by energy insecurity, climate change and falling farmer incomes. The Indian government has enthusiastically adopted a second-generation feedstock – the oilseed-bearing shrub, Jatropha curcas – for an ambitious national biodiesel program. Studies estimating the production capacity and potential land use implications of this program have typically assumed that the ‘waste land’ slated for Jatropha production has no economic value and that no activities of note will be displaced by plantation development. Here we examine the specific local impacts of rapid Jatropha plantation development on rural livelihoods and land use in Rajasthan, India. We find that in Jhadol Tehsil, Jatropha is planted on both government and private land, and has typically displaced grazing and forage collection. For those at the socioeconomic margins, these unconsidered impacts counteract the very benefits that the biofuel programs aim to create. The Rajasthan case demonstrates that local land-use impacts need to be integrated into decision-making for national targets and global biofuel promotion efforts.     

Molecular characterisation of Jatropha curcas L. genetic resources from Chiapas, México through AFLP markers

The aim of this study was to evaluate the genetic diversity of Jatropha curcas in Chiapas, México using AFLP markers. The AFLP technique allowed us to estimate the genetic relationships in the germplasm of J. curcas and to detect a high level of polymorphism. Analysis of the frequency and distribution of polymorphic fragments allowed us to detect the highest number of rare fragments in one single accession (e.g., accession number 1 from Tuxtla Chico). Besides being an accession that exhibits traits of agronomic importance (such as the presence of 100% pistillated flowers), this diversity of rare fragments may allow for development of markers for identification of this accession and/or development of markers linked to this trait. In addition, very divergent collections have been detected from regions where high average oil content and other characters associated with productivity have been found. Moreover, the analysis of genetic relationships, Analysis of Molecular Variance (AMOVA) and the diversity index (DI = 60%) confirm a broad gene pool in the J. curcas germplasm from Chiapas, México. The high diversity found within the accessions showed non-random mating between groups and/or regions of accessions of J. curcas, which complicates the selection of representative collections.     

Expression profiles of genes involved in fatty acid and triacylglycerol synthesis in developing seeds of Jatropha (Jatropha curcas L.)

Jatropha (Jatropha curcas L., Euphorbiaceae), a potential biodiesel plant, has created tremendous interest all over the world for the use of its seed oil as a commercial source of biodiesel. Due to the unreliability of oil content in its seeds and low economic returns planting of jatropha in agriculture was restricted. Investigating the molecular basis of storage lipid accumulation during seed development is an immediate need to understand genetic factors regulating storage lipid biosynthesis in jatropha seeds. In this study, we characterized the seed development and lipid accumulation from female flowers pollinated to mature seeds, and investigated temporal expression profiles of 21 lipid genes involved in different steps of the pathways leading to fatty acid and TAG synthesis within jatropha developing seeds using quantitative real-time PCR technology. Concomitantly, 17 genes increased their expression levels in developing seeds compared to their expression in leaf, but showed various temporal expression patterns and different relative-maximum ratio ranging from 2.8 to 1,919,280-fold in developing seeds. Five gene groups with distinct temporal patterns were identified by clustering analysis of expression data. Two gene groups including 15 genes presented up-regulated expression patterns correlated with storage lipid accumulation in developing seeds. This study provided not only the initial information on promoter activity for each gene, but also a first glimpse of the global patterns of gene expression and regulation, which are critical to understand the molecular basis of lipid biosyntheses, identifying the rate-limiting genes during seed development and to create improved varieties by genetic engineering.     

Enhancement in hydrogen production by co-cultures of Bacillus and Enterobacter

Defined co-cultures of hydrogen (H₂) producers belonging to Citrobacter, Enterobacter, Klebsiella and Bacillus were used for enhancing the efficiency of biological H₂ production. Out of 11 co-cultures consisting of 2–4 strains, two co-cultures composed of Bacillus cereus EGU43, Enterobacter cloacae HPC123, and Klebsiella sp. HPC793 resulted in H₂ yield up to 3.0 mol mol⁻¹ of glucose. Up-scaling of the reactor by 16-fold resulted in a corresponding increase in H₂ production with an actual evolution of 7.44 L of H₂. It constituted 58.2% of the total biogas. Continuous culture evolution of H₂ by co-cultures (B. cereus EGU43 and E. cloacae HPC123) immobilized on ligno-cellulosic materials resulted in 6.4-fold improvement in H₂ yield compared to free floating bacteria. This synergistic influence of B. cereus and E. cloacae can offer a better strategy for H₂ production than undefined or mixed cultures.     

Soil texture effects on the development of Jatropha seedlings - Mexican variety ‘piñón manso’

There is considerable disagreement on the effects of different soil conditions on the growth of Jatropha curcas L., although different reports agree on some factors, such as a preference for sandy soils over clay soils. This paper presents results on the growth of seedlings of a low-toxic Mexican cultivar in three different soils from the SE of Mexico. The Mexican seeds were sown in soils of different textures: sandy, sandy-loam and clay-loam. The germinated seedlings were monitored during a period of one month. Then, they were uprooted to record below and above ground morphological parameters and dry matter weight. Stem lengths, root collar diameter, length and diameter of the five main roots, number of true leaves and dry matter were analyzed using one-way ANOVA. The soils used were subjected to a chemical analysis to determine soil nutrient contents, which revealed that clay-loam soil had the highest nutrient content, followed by the sandy-loam, while sandy soil presented the lowest values. It was found that seedlings grown in sandy-loam soil were significantly taller than those in clay-loam and sandy substrates (P ≤ 0.05). Root collar diameter, root diameter, number of true leaves and dry matter weight did not present significant differences between plants grown in sandy-loam and clay-loam soils, however they showed significant differences when compared with plants grown in sandy soil. Therefore it can be concluded that development of seedlings in sandy-loam soils was greater, followed by those in clay-loam, while the poorest performance of the seedlings was recorded in sandy soil.     

Long term storage stability of Jatropha curcas biodiesel

The objective of this work was to study the long term storage stability of JCB (Jatropha curcas biodiesel). For the objective JCB was mixed with PY (Pyrogallol) and different metal contaminants. JCB samples were stored for 6 months in open air exposed to sunlight. Different properties were checked with respect to time. It was found that stability of fresh JCB was not acceptable as per EN 14214. When PY was mixed with JCB, it stability increased and 200 ppm of PY was sufficient to make fresh and pure JCB stable for almost 6 months. Viscosity (n), PV (peroxide value) and AV (acid value) increased with respect to time. Unsaturated fatty acid composition was also checked with respect to time. From the experiment it was clear that as oxidation deterioration advanced, linoleic and linolenic acid methyl esters decreased and the fraction of oleic acid methyl became relatively high with respect to storage time.