Raw Materials For Biofuels Research Articles

Regional and temporal sustainability assessment of agricultural-based biodiesel

Although the world energy mix is still strongly dependent on fossil fuels, biofuels have been gaining market share, especially in the transport sector. The main biofuel raw materials are those produced by agropastoral systems that use large expanses of land. The present work presents an innovative method of sustainability assessment of biodiesel, combining temporal and regional approaches based on its three pillars. The method aims to ascertain whether a determined region, whose main economic activities are agropastoral and processing of agricultural raw materials, is moving toward or away from sustainability. The work integrates tools to evaluate land use change from satellite images with life-cycle assessment, to obtain greenhouse gas (GHG) emissions as the environmental metric. The economic and social metrics are the time derivative of per capita gross domestic product and the school enrolment ratio. The improvement of agropastoral/industrial activities in the region directly reflects the changes of the three metrics. The proposed method was applied to assess the sustainability of biodiesel produced from soybean oil and beef tallow in a micro-region of Central Brazil, in the period from 2003 to 2013. The case study revealed a reduction of 10% in sustainability, with improvements of 344% and 15% in the economic and social metrics but a decline of 1106% in the environmental metric. The results also showed that for both biodiesel made from soy oil and tallow, land use change is responsible for 97% of GHG emissions. The conclusion is that the implementation of automation of agricultural processes, with consequent increase in productivity, besides diminishing the environmental impact, would lead to an increase in gross domestic product indices and in the average schooling level, thus contributing to reduce social inequalities and increase the sustainability of agricultural-based biodiesel.

Botanical characteristics, potential uses and cultivation possibilities of mustards in Turkey: a review

The mustard species [(Brassica juncea (brown mustard),B. nigra (black mustard),B. rapa syn. B. campestris (field mustard or turnip), and Sinapis alba (white mustard or yellow mustard)] constitute important genetic resources and sources of raw materials to large number of agrobased industries in Turkey and elsewhere. S. alba is usually used as a condiment in dry form. B. nigra is used as a condiment and as vegetable with dietary fibre, vitamin C, and other anticancer compounds. B. juncea is used for oil and as spice. B. rapa is popularly used for biofuel raw material. However, there is poor focus on their breeding and varietal development for industrial purposes like biofuel production etc. Therefore, they are rightly called neglected crops in Turkey. The aim of this study is to provide a comprehensive information about appropriate mustard species that can be evaluated in different sectors and bring innovations in laying new scientific foundations of the subject. As such, this paper has compiled information about economic importance, general characteristics, and ethnobotanical uses of the mustards found in Turkey.

Improving the economic efficiency of production biodieselfuel

In order to optimize the performance of transportation works for the transportation of raw materials for the production of biodiesel fuel, the article examines the technology when oil from oilseeds is obtained at the processing points where they are grown. The resulting oil is transported to a biodiesel production plant. The methodological bases for calculating the optimum distance from oilseed grain storage sites to a mechanized oil production point are presented. Possible ways of the efficiency improving of production of biofuel at the stage of the planning are presented. Methodical bases of calculation of distance to mechanized points for biofuel production are given. A formula for determining the optimum capacity of an item for the processing of oil seeds and for obtaining raw materials for the production of biofuels has been derived. It is established that optimum transportation distance of rape is 14,4 km, productivity of the rapeseed oil processing plant is 21280 tons/year and for 25% of the oil yield 5320 tons of biofuel raw materials can be obtained, when the total overhead costs are Zv = 360000 UAH / year; specific costs of transportation of raw materials сp = 2,6 UAH/ (тkm); yield of oilseed rape = 1 t / ha (100 t / km2); the density of the placement of fields a = 0.4. The developed method can be used to calculate the location, performance of points for the manufacture of briquettes or pellets. The direction of increasing the efficiency of biodiesel production at plants at the stage of their planning is to determine the optimal annual productivity of the plant, taking into account transport costs for the transportation of raw materials - oil. The optimum distance of transportation of oil and productivity of the plant for biodiesel production is established for the cost of transportation - 2.6 UAH / t • km, overhead costs 13000000 UAH, direct costs for the production of 1 ton of biodiesel fuel - 25000 UAH Therefore, the optimal distance of transportation of oil for the production of biofuels - 101 km, the capacity of the plant - 58923 tons. The dependence of the cost of production of biodiesel fuel on the distance of transportation of oil is calculated: for distance to plant 40 km – the cost of biofuel production – 25596 UAH/t, for 60 km – 25496 UAH /t, for 80 km – 25462 UAH /t, for 100 km – 25459 UAH /t, for 120 km – 25471 UAH /t, for 140 km – 25493 UAH /t. The proposed method provides an opportunity to determine the optimum productivity of the plant for the processing of organic raw materials into biofuels, taking into account the distance of its transportation at the design stage. Key words: biodiesel, economic efficiency, production optimization, direct costs, overhead costs.

Исследование биосинтеза бактериальной наноцеллюлозы продуцентом Medusomyces gisevii Sa-12 на ферментативном гидролизате продукта щелочной делигнификации мискантуса

A high demand for bacterial nanocellulose (BNC) in various economic sectors has resulted in intensification of studies aimed at searching for ways of reducing the cost of its production. BNC on an industrial scale is obtained using synthetic nutrient media, the cost of which may amount to 30–60% of the total cost of the process. Therefore, the study of BNC biosynthesis using low-cost nutrient media, such as food and cellulosic waste and other alternative sources of raw materials, seems to be highly relevant. The biomass of miscanthus currently used as a raw material for biofuels may become such an alternative source. Miscanthus is characterised by availability, low cost and annual renewability on an industrial scale. This study was aimed at investigating the BNC biosynthesis process from the enzymatic hydrolyzate obtained by alkaline delignification of miscanthus. The delignification process involved treatment of the plant with a dilute sodium hydroxide solution at ambient pressures. Enzymatic hydrolysis of the obtained substrate was carried out in a 11L-fermenter. For the first time, BNC was successfully obtained in a nutrient medium from an enzymatic hydrolyzate produced by alkaline delignification of miscanthus. The symbiotic culture of Medusomyces gisevii Sa-12 characterised by a high adaptive potential was used as a producer. The maximum specific growth rates were 0.360 and 0.384 day -1 for yeast and acetic acid bacteria, respectively. Consumption of reducing substances was observed to proceed in two stages: the rate constant of substrate utilisation at the first and the second stages were equal to 0.464 day and 0.034 day -1 , respectively. The highest yield of BNC was 5.14% on the 14th day of cultivation, which is 1.8 times lower than that on a synthetic nutrient medium. Although the nutrient medium of the enzymatic hydrolyzate obtained by alkaline delignification of miscanthus is not biologically pure, Medusomyces gisevii Sa-12 shows a high technological potential and ability to synthesize a chemically pure BNC even under adverse conditions.

Bioactive Ingredients from Microalgae: Food and Feed Applications

Microalgae (green or blue-green ones) are among the most important organisms on the world, with a versatile and adaptive metabolism. They are able to synthesize bioactive molecules (mainly secondary metabolites such as unsaturated fatty acids, pigments, amino acids) with biomedical applications, enhancement of the nutritional value of food, animal feed/aquaculture, as well with impact on the environmental protection ( as raw materials for biofuels). Last decade, by a targeted selection of wild microalgae strains, their cultivation in farms developed in parallel with the bioreactors’products. There are nowadays cultivated at industrial scale especially Dunaliella salina p., Spirulina platensis, Hematococcus pluvialis or Chlorella vulgaris as valuable resources of polyunsaturated lipids and sterols, proteins, polysaccharides, carotenoid pigments, vitamins, minerals with antioxidant, antibacterial or antiviral effects. This review presents a systematic approach on the recent literature data collected the last years, underlying their morphologic and biochemical potential, the advanced technologies to use the bioactive components of different microalgae, new formulations which incorporate, stabilize and store their bioactivity and increase the bioavailability of their components in food and feed. Although their morphologic and biochemical potential is well described, there are presented new data on their bioactive components and formulations using emerging technologies for new application approaches which aims their use as ingredients in added value products for food, cosmetics and feed industry, to be exploited for commercial use. This review updated the last findings in these areas, underlined the reason for the scientific and technological advances, due to their huge potential, not only in environment, energy, but more and more as ingredients for food and feed/ aquaculture products, in the future.

PROSPECTS AND EFFICIENCY OF BIODIESEL PRODUCTION IN UKRAINE FROM OILSEED CROPS

PROSPECTS AND EFFICIENCY OF BIODIESEL PRODUCTION IN UKRAINE FROM OILSEED CROPS

Utilization of Gendruwo waste (Sterculia foetida Linn.) as briquettes

Gendruwo plant (Sterculia foetida Linn.) or more commonly known as Kepuh is a plant species in Indonesia that origination from East Africa, Asia and Australia. This plant can be used as biofuel raw material in the form of biodiesel and bio-oil. Gendruwo plant seeds contain vegetable oil which consists of fatty acids namely stercylat acid (C19H34O2). The seeds that have been extracted into biodiesels leave the residue or waste in the form of gendruwo seed pulp. From the analysis, the remaining extract or debris can still be used as fuel because it contains the remaining fatty acid compounds. These gendruwo dregs can be used as coal substitute briquettes. Gendruwo seed waste briquettes have quality advantages than coal briquettes or coconut shell briquettes because they have longer coal resistance, which are environmentally friendly and also produce a better heat.

Sterol and Sphingoid Glycoconjugates from Microalgae.

Microalgae are well known as primary producers in the hydrosphere. As sources of natural products, microalgae are attracting major attention due to the potential of their practical applications as valuable food constituents, raw material for biofuels, drug candidates, and components of drug delivery systems. This paper presents a short review of a low-molecular-weight steroid and sphingolipid glycoconjugates, with an analysis of the literature on their structures, functions, and bioactivities. The discussed data on sterols and the corresponding glycoconjugates not only demonstrate their structural diversity and properties, but also allow for a better understanding of steroid biogenesis in some echinoderms, mollusks, and other invertebrates which receive these substances from food and possibly from their microalgal symbionts. In another part of this review, the structures and biological functions of sphingolipid glycoconjugates are discussed. Their role in limiting microalgal blooms as a result of viral infections is emphasized.

Massa seca e teores de nutrientes de plantas de milho sob efeito de águas salinas e biochar

O milho é cultivado em todo o Brasil para uso na alimentação humana e animal e como matéria prima de biocombustíveis e indústria. Sua produtividade é prejudicada pela degradação de água e solo, da qual a salinização é grave na região semiárida. Três experimentos foram realizados em solos (Argissolo, Cambissolo e Neossolo flúvico) do estado do Rio Grande do Norte para avaliar o efeito do biochar sobre a massa seca e nutrientes de plantas de milho irrigado com águas salinas. Os solos preenchiam colunas de PVC dispostas em casa de vegetação da Universidade Federal Rural do Semiárido, em Mossoró. O delineamento era inteiramente casualisado em esquema fatorial com quatro repetições. Os fatores estudados foram doses de biochar (0; 0,5; 1,0; e 1,5 %) e níveis de salinidade da água de irrigação (0,57; 2,65 e 4,5 dS m-1). O biochar foi obtido da carbonização de Prosopis juliflora (Sw.). Aos 40 dias após emergência determinou-se a massa seca da parte aérea e o teor de N, P, K, Ca e Mg das plantas. Os dados foram submetidos à análise de variância e análise de regressão. As respostas da massa seca e teores de nutrientes do milho indicam que o biochar pode mitigar a salinidade da água de irrigação, dependendo da dose aplicada e do tipo de solo.

Foreign cry1Ac gene integration and endogenous borer stress-related genes synergistically improve insect resistance in sugarcane

BackgroundSugarcane (Saccharum spp. hybrids) is considered the most globally important sugar-producing crop and raw material for biofuel. Insect attack is a major issue in sugarcane cultivation, resulting in yield losses and sucrose content reductions. Stem borer (Diatraea saccharalis F.) causes serious yield losses in sugarcane worldwide. However, insect-resistant germplasms for sugarcane are not available in any collections all over the world, and the molecular mechanism of insect resistance has not been elucidated. In this study, cry1Ac transgenic sugarcane lines were obtained and the biological characteristics and transgene dosage effect were investigated and a global exploration of gene expression by transcriptome analysis was performed.ResultsThe transgene copies of foreign cry1Ac were variable and random. The correlation between the cry1Ac protein and cry1Ac gene copies differed between the transgenic lines from FN15 and ROC22. The medium copy lines from FN15 showed a significant linear relationship, while ROC22 showed no definite dosage effect. The transgenic lines with medium copies of cry1Ac showed an elite phenotype. Transcriptome analysis by RNA sequencing indicated that up/down regulated differentially expressed genes were abundant among the cry1Ac sugarcane lines and the receptor variety. Foreign cry1Ac gene and endogenous borer stress-related genes may have a synergistic effect. Three lines, namely, A1, A5, and A6, were selected for their excellent stem borer resistance and phenotypic traits and are expected to be used directly as cultivars or crossing parents for sugarcane borer resistance breeding.ConclusionsCry1Ac gene integration dramatically improved sugarcane insect resistance. The elite transgenic offspring contained medium transgene copies. Foreign cry1Ac gene integration and endogenous borer stress-related genes may have a synergistic effect on sugarcane insect resistance improvement.

Análisis de competitividad y rentabilidad de producción de biodiesel de granos de moringa en Chiapas y Yucatán, México


 
 
 La producción de biocombustibles a nivel mundial ha crecido exponencialmente en los últimos años, su desarrollo ha estado ligado al aumento del precio del petróleo y a la creciente concientización social desarrollada en torno al cuidado del medio ambiente. El mundo apuesta actualmente por el biodiesel como alternativa parcial a los combustibles de origen fósil dado que procede de fuentes renovables y permite reducir, de modo significativo, las emisiones de dióxido de carbono a la atmósfera. Los avances tecnológicos amplían la gama de materias primas para biocombustibles, algunas de las cuales; como los pastos y los árboles de crecimiento rápido pueden crecer en regiones menos fértiles y más propensas a la sequía y compiten menos con cultivos para la producción de alimentos humano y animal como el maíz, la caña de azúcar, la soya y la colza, tal es el caso de Moringa oleifera que en la actualidad se cultiva prácticamente en todas las regiones tropicales, subtropicales y semiáridas del mundo, ya que puede crecer en condiciones de escasez de agua. El objetivo de esta investigación fue evaluar económicamente la producción integral de biodiesel con granos de moringa considerando dos zonas agroecológicas de producción de materia prima, el Soconusco, Chiapas y Uxmal, Yucatán y su transformación a biodiesel mediante el proceso de transesterificación industrial en una planta piloto. Para las fases agrícola e industrial, se generaron los indicadores de rentabilidad como la tasa interna de retorno (TIR), valor actual neto (VAN) y punto de equilibrio (PE). Los resultados indicaron que la producción agrícola es altamente rentable debido al aprovechamiento adicional de las hojas como coproducto con TIR de 109 y 130% para el Soconusco, Chiapas y Uxmal, Yucatán, respectivamente, mientras que la fase industrial, considerando cero subsidios a la producción de biodiesel resultó rentable con TIR de 53% en Uxmal, Yucatán y 37% en el Soconusco, Chiapas.
 
 

Complete characterization of pruning waste from the lechero tree (Euphorbia laurifolia L.) as raw material for biofuel

Abstract The aim of this study is to conduct a complete characterization of the pruning waste from the lechero tree. This tree species is of particular relevance in Ecuador for its use as biomass since it yields large amounts of pruning waste, it has a high propagation capacity and very fast growth, for both the trunk and branches. The pruning waste consists of a mixture of wood and leaves, which are subjected to caloric analysis, elemental analysis, proximate analysis, thermogravimetric analysis and fermentability. The average dry pruned biomass obtained per tree is 9.95 kg, with a 1.49 kg standard deviation. The average ratio of leaves in pruned biomass is the 40%. Regression model to determine pruning waste biomass from plant measurements was obtained with 0.7 of r2. The calorific value of these residues is 19 MJ/kg average. N and ash content is influenced by leaf content. A leaf content less than 25% represent N content lower than 1%, and 6% ash content. Prediction models to higher heat value (kJ/kg) based on elemental, proximate and structural analysis is presented.

Application of MSSIP-2 nutrient in marine phytoplankton culture to support the production of biomass for biofuel industry

A research on the application of MSSIP-2 nutrient in marine phytoplankton culture has been conducted to produce biomass to be used as raw material for biofuel. Marine phytoplankton was cultivated using the nutrient media and the growth rates were studied by measuring the cell solidity at various growth times. Seven phytoplanktons; Isochrysis aff galbana, Spirulina sp., Thalassiosira sp., and Nitzchia sp., Chlorella vulgaris, Chaetoceros calcitrans and Isochrysis tahiti were used in the research. The experimental temperature, salinity, and pH of the media were measured and the specific growth rates of phytoplanktons were determined using the first order rate equation. Results showed that the highest specific growth rate was given by Chlorella vulgaris (0.0322 cells/hour) and the lowest one was by Thalassiosira sp. (0.0277 cells/hour). The highest biomass weight was obtained from Isochrysis aff galbana (0.329 g), whereas the lowest one (0.27 g) was from Nitzchia sp. The carbohydrate content was various, the highest content was 34.07% found in Isochrysis aff galbana and the lowest was 28.16% in Thalassiosira sp.

Root lodging is a physical stress that changes gene expression from sucrose accumulation to degradation in sorghum

BackgroundSorghum (Sorghum bicolor L.) is used as a raw material for biofuels because it accumulates sugars at high levels in the stem. Lodging of sorghum occurs when the soil is wet and very high winds blow across the field. In root lodging, the roots are pulled loose from the soil, causing the plant to fall over. Lodging reduces the yield of nonstructural carbohydrates. It is not yet clear which genes show changes in expression when sorghum falls over. We compared whole-gene expression in the mature stems of intact and lodged sorghum plants, with a focus on comparisons from the perspective of differences in sugar accumulation or degradation.ResultsLodging decreased sucrose content, starch content, and ratio of sucrose to total sugars in the stems of the sorghum cultivar SIL-05. Particular paralogs of SWEET and TMT family genes, which encode sucrose or hexose transporters, or both, were significantly highly expressed in intact or lodged sorghum stems. In intact stems, genes encoding the glucose-6-phosphate translocator, aquaporins, and enzymes involved in photosynthesis and starch synthesis were highly expressed. In lodged sorghum stems, expression of genes associated with sucrose or starch degradation or energy production was increased. Notably, expression of genes encoding enzymes catalyzing irreversible reactions and associated with the first steps of these metabolic pathways (e.g. INV, SUS, and hexokinase- and fructokinase-encoding genes) was significantly increased by lodging. Expression of SUT, SPS, and SPP was almost the same in intact and lodged sorghum.ConclusionsSpecific paralogs of sucrose-associated genes involved in metabolic pathways and in membrane transport were expressed in the stems of sorghum SIL-05 at the full-ripe stage. Root lodging drastically changed the expression of these genes from sucrose accumulation to degradation. The changes in gene expression resulted in decreases in sugar content and in the proportion of sucrose to hexoses in the stems of lodged plants.

Improving Saccharification of Oil Palm Shell by Acetic Acid Pretreatment for Biofuel Production

Lignocellulosic biomass is utilized as raw materials for biofuel and electricity production in different ways. The major bottleneck of biofuel production from lignocellulosic biomass is the saccharification to produce small molecules of sugars that subsequently converted to value added compounds. Pretreatment is performed before saccharification to enhance conversion rate. In this study, acetic acid was selected to pretreat oil palm shell to enhance the production of reducing sugars in enzymatic saccharification reaction. To obtain the maximum sugars, Response Surface Methodology (RSM) with Box-Behnken design was applied in the pretreatment. Three variable factors, including reaction time, reaction temperature and acetic acid concentration were varied with three levels. The generated model has high correlation coefficient (R2) at 0.9725 indicating the high confident level. Based on the model, the maximum reducing sugars at 40.408 mg/g-biomass could be obtained at optimum condition (107.30 oC reaction temperature, 30 min reaction time and 8.24% acid concentration). The results of this study suggested the benefit of using acetic acid for improvement of saccharification of lignocellulosic biomass to biofuel.

Genome-wide analysis of the cellulose synthase-like (Csl) gene family in bread wheat (Triticum aestivum L.)

BackgroundHemicelluloses are a diverse group of complex, non-cellulosic polysaccharides, which constitute approximately one-third of the plant cell wall and find use as dietary fibres, food additives and raw materials for biofuels. Genes involved in hemicellulose synthesis have not been extensively studied in small grain cereals.ResultsIn efforts to isolate the sequences for the cellulose synthase-like (Csl) gene family from wheat, we identified 108 genes (hereafter referred to as TaCsl). Each gene was represented by two to three homeoalleles, which are named as TaCslXY_ZA, TaCslXY_ZB, or TaCslXY_ZD, where X denotes the Csl subfamily, Y the gene number and Z the wheat chromosome where it is located. A quarter of these genes were predicted to have 2 to 3 splice variants, resulting in a total of 137 putative translated products. Approximately 45% of TaCsl genes were located on chromosomes 2 and 3. Sequences from the subfamilies C and D were interspersed between the dicots and grasses but those from subfamily A clustered within each group of plants. Proximity of the dicot-specific subfamilies B and G, to the grass-specific subfamilies H and J, respectively, points to their common origin. In silico expression analysis in different tissues revealed that most of the genes were expressed ubiquitously and some were tissue-specific. More than half of the genes had introns in phase 0, one-third in phase 2, and a few in phase 1.ConclusionDetailed characterization of the wheat Csl genes has enhanced the understanding of their structural, functional, and evolutionary features. This information will be helpful in designing experiments for genetic manipulation of hemicellulose synthesis with the goal of developing improved cultivars for biofuel production and increased tolerance against various stresses.

Crambe Growth in a Soil Amended with Biochar and under Saline Irrigation

ABSTRACTBiochar is the term given to biomass subjected to the process of change in the composition by the action of high temperatures. Advantages of biochar in soil quality have been reported, including amelioration of salinity effects. Crambe has great potential to figure as raw material for biofuel, since it naturally contains up to 60% of erucic acid. This study evaluated crambe growth in a soil amended with biochar and irrigated with saline waters. A greenhouse experiment was conducted following a completely randomized design with five levels of biochar, two irrigation water supplies, and four replications. Parameters related to soil chemical properties, crambe growth, oil, and macronutrient contents were evaluated. Biochar presented significance for pH, electrical conductivity (EC), organic matter (OM), phosphorus (P), sodium (Na), and potassium (K) contents. Crambe growth parameters decreased with the doses of biochar. Oil and macronutrient contents were in accordance to previous studies.

The Response of Spring Wheat Cultivars to Arbuscular Mycorrhizal Colonization under Salinity Stresses

Wheat is an important crop, playing inevitable roles in human life, ranging from major food resource to raw material for biofuel. However, due to the dramatically reduced available arable areas and increasingly severe abiotic and biotic stresses, wheat production nowadays faces extreme challenges.. Many approaches have been explored to increase wheat yield including development of new cultivars. One of the most promising approaches is the application of the naturally existent arbuscular mycorrhiza (AM), a mutualistic symbiosis originated over 400 million years ago. AM have long been known to form mutualistic symbiosis with various plants to enhance yield production and to improve stress tolerance, especially drought and salinity. But the benefits vary among AM strains and plant species. Therefore, the objective of the study was to investigate the influence of four AM strains colonized on four selected spring wheat varieties under three salt concentrations (0, 50, 100 mmol/L). The results demonstrated that wheat inoculated with arbuscular mycorrhizal strains Funneliformis mosseae and Rhizoglomusirregulare mitigated yield losses caused by increased salinity stresses as well as strengthened root growth in comparison with non-inoculated plant controls. Salinity stress, however, had non-significant negative effects on most variables, except for grain yield, root surface area and root dry weight, in which a significant decrease was observed in root surface area and root dry weight with the increasing of saline concentration.

Heavy Metals in Soil and Sugarcane Accumulation in Agricultural Area along Huanjiang River in Guangxi, China

Heavy metal contaminations to farmland soil is a common threaten to crop yield and food safety, phytoremediation with economic plants with high bio-accumulation is a sustainable approach to recover polluted farmland. As a high ethanol yield crop, sugarcane has attracted increasing industrial interest as a raw material for biofuel and the risk of heavy metal in it is negligible if the sugar produced is to be fermented into ethanol rather than by consumed. This study is to do a preliminary investigation if sugarcane is a suitable crop for phytoremediation in heavy metal polluted farmland in a context of geographic conditions in southern China, thirty-eight soil and sugarcane samples were collected in five villages in a typical agricultural county called Huangjiang which is located in the Huanjiang River Basin in Guangxi province. Sugarcane is widely cultivated in Huangjiang as one of the major economic crops, meanwhile, pollutions induced by mining and ore-extraction in this area has resulted in heavy metals entering the farmland soils. Samples collected were used to assess the correlation of the level of heavy metals in the soil, and their concentrations in roots, sections of stems and leaves. Seven heavy metals were selected in this study and the results showed that most of the toxic heavy metals intake by sugarcane accumulated in the roots, while only a small portion is transferred to the stems and leaves. The study initially outlined sugarcane as a potential candidate for phytoremediation in farmland polluted by heavy metals with economic motivate in this subtropical geographical background.

Growth and photosynthetic activity of Botryococcus braunii biofilms

Botryococcus braunii is a green microalga capable of producing large amounts of external long-chain hydrocarbons suitable as a source of biofuel. There have been several studies indicating that cultures of B. braunii can reduce the energy and water requirement for mass biofuel production, especially if non-destructive extraction methods for milking hydrocarbons are used. Growing microalgae as a raw material for biofuel using conventional liquid-based cultivation (i.e., raceway ponds) has yet to be shown to be economically successful. An alternative solid growth (biofilm) cultivation method can markedly reduce the energy requirements and costs associated with the harvesting and dewatering processes. We evaluated the growth of biofilms of several strains of B. braunii (from races A, B, L and S) and found that three of the four tested races successfully grew to stationary phase in 10 weeks with no contamination. Among all races, B. braunii BOT22 (race B) reached the highest biomass and lipid yields (3.80 mg dry weight cm−2 day−1 and 1.11 mg dry weight cm−2). Irrespective of the race, almost all photosynthetic parameters (FV/F0, PIABS and the OJIP curve) showed that the biofilm cultures were more stressed during lag and stationary phases than in logarithmic phase. We also studied the Botryococcus biofilm profiles using confocal microscopy and found that this method is suitable for estimating the overall biomass yield when compared with gravimetric measurement. In conclusion, the growth characteristics (biomass and lipid) and photosynthetic performance of all races indicated that B. braunii BOT22 is the most promising strain for biofilm cultivation.