The EU Directive on the promotion of the use of biofuels or other renewable fuels for transport (CO M 2003/30/EC) states that the proportion of biofuels in 2010 must make 5.75% of non-renewable fuels, but in 2020 - 10%. The only way for Latvia to fulfil the Directive 2003/30/EC is to use winter rye because it is one of the oldest cereals grown in Latvia, and Latvia has a long-lasting experience in growing it. A field trial of winter rye (Secale cereale L.) was arranged in the Agricultural Science Centre of Latgale from 2005 to 2007. The influence of four winter rye varieties and five fertilizer rates on grain yield and starch content was researched for three years. The year (factor A), the varieties (factor B), the fertilizer rates (factor C), and the interaction of factors AB, AC , BC, and ABC significantly influenced the yield of grain and the starch content with 95% probability. It is recommended to use good quality grain with high starch content and low protein content for bioethanol production. The varieties of winter rye 'Kaupo', 'Amilo', and 'Walet' are the most suitable for ethanol production in Latgale region.

Grain after enzymatic treatment, which is a starch-containing raw material, is used for ethanol production. Bioethanol production in Latvia began in 2006. Extraction of biofuels is a clean process, because the byproduct is used in various sectors of the economy. The bioethanol in Latvia was derived primarily from winter wheat, winter rye, and winter triticale. The objective of the research is to determine the different nitrogen fertiliser rates required for winter cereal crop yields and bioethanol outcome. The trials were carried out from 2005 to 2008 in Agricultural Science Centre of Latgale (Latvia). The method (ethanol outcome) is based on fermentation of saccharified cereal samples by yeast Saccharomyces cerevisiae followed by the calculation of ethanol outcome and speed of fermentation. The highest starch content was in winter wheat and winter triticale grain, but the lowest - in winter rye grains. A close negative correlation (p is less than 0.05) was found for winter triticale and winter wheat between the ethanol outcome and thousand grain weight. Production of bioethanol from rye starch content is used with full utilisation of grain. The winter wheat has the largest ethanol outcome from one hectare.

One of the primary reasons for expanding the production and use of biofuels is the potential environmental benefit that can be obtained from replacing fossil fuels with fuels derived from renewable biomass resources. This investigation examines the impact of biofuels on the environment directly from the practical view point analysing how the internal combustion engine emission concentration changes using the most common first-generation biofuels in Latvia – biodiesel, rapeseed oil and bioethanol. Laboratory experiments were performed on a chassis dynamometer Mustang MD1750, but the content of exhaust gases components was determined by the AV L SESAM FTIR measurement system. Investigation shows that the trends of different exhaust gas component changes, which would be the same for all investigated fuels, don't exist, i.e., each vehicle and biofuel type or blend is particular and has to be analysed separately. In comparison with fossil diesel, running the car VW Golf on rapeseed oil the average reduction of NOx was 10%, but SO2 – 59%. The CO, CO2, unburned hydrocarbon and mechanical particle emissions were higher. Running the car Opel Vectra on biodiesel the amount of NOx in comparison with fossil diesel increased in average by about 12%, the amount of mechanical particles and unburned hydrocarbons decreased quite significantly, but just a small increase of CO and SO2 was observed. Testing the car VW Passat on gasoline-bioethanol blends increase of the bioethanol content in the fuel blend increased also the NOx content in exhaust gases, but the content of CO, CO2 and NH3 decreased.

Bioethanol can be used for food production and to partially replace fossil fuel. Bioethanol is mainly produced from renewable biomass that contains sugars, starch or lignocellulose. The main raw materials for production of bioethanol are cereals, maize (Zea mays), sugarbeets (Beta vulgaris sacccharifera) and other plant species. During the trial that took place in State Stende Cereals Breeding Institute during a three year period (from 2009/2010 to 2011/2012) we examined the suitability of grain from winter wheat (Triticum aestivum L.), triticale (×Triticosecale Wittm) and rye (Secale cereale L.) for the production of bioethanol. Three varieties of each species were used in the trial. During the trial period the grain yield, the ethanol outcome (L tE-1) and the ethanol yield (L haE-1) were determined. It was established that during three years wheat and triticale provided the highest starch content (more than 700 g kgE-1) of the grain as well as the highest ethanol outcome (L tE-1). These species provided both high grain yield (more than 9 t haE-1 on average) and the highest ethanol yield (3300 – 4665 L haE-1). The choice of variety was also important as both the grain starch content and the grain yield depend on the genotype of the variety.

One of the biodiesel production problems is occurrence of a significant quantity (about 10%) of the by-product – glycerol. This problem is offered to solve by adaptation of bacteria Zymomonas mobilis, which is notable for ethanol production facilities. To be able to process glycerine into ethanol using Z.mobilis bacteria, the bacteria must be modified. At the same time, computer modelling analysis is required to assess specific modification affectivity in interconnection with other processes in bacteria. Computer model results of simulated experiment to understand and predict that the cells and biological processes are essential to reduce the number of experiments. This in turn reduces the necessary financial resources and time, bio-medical biotechnology, pharmaceutical and environmental problems. The model describes conversion of glycerol into bioethanol in Z.mobilis bacterial cell. First phase of model creation is creation of a structure model based on biochemical reactions using computer software CellDesigner. On the second phase of model creation, kinetic parameters which are available in literature were identified. Using the databases KEGG, SABIO-RK, BRENDA, reactants, kinetic parameters and reaction equation types were defined. Dynamic model of Z. mobilis biochemical network was created using computer software Copasi. The dynamic model describes conversion of glycerol into bioethanol in Z.mobilis bacterial cell. In this time simulation data of the computer model of natural organisms are not to confirm laboratory experimental data. Simulation data of the computer model are not correct to prevent this problem is required parameter estimation in computer software COPASI.

Metabolic analysis is one of the research focuses of systems biology. Two aspects of metabolic networks -network topology and stoichiometry - are what current researchers are most interested in, and both studies have revealed significant information. The research of the stoichiometric matrix of metabolic network has generated a series of powerful methodologies such as flux balance analysis (FBA). For FBA different methods execution are used different software like COBRA Toolbox and FBA-SimVis. The aim of this paper is to compare and analyze functionality of these two toolboxes, metabolic network data conformation conditions, and to compare all available FBA methods comparison in calculation possibilities and visual interpretation way. FBA, when analyzing all fluxes using different options, gives results in its metabolic network flow chart, although Cobra Toolbox returns the results in the matrix in number formats. FBA-SimVis for Steady state metabolic network models analysis is provided for a small metabolic network, because making some FBA analysis there are a ten possibilities to change an unlimited count of variables, to choose or change or optimize reactions as variables. Cobra Toolbox for Steady state metabolic network models analysis is provided for greater metabolic networks with hundreds or thousands of reactions. It allows changing an unlimited count manipulating and optimizing reactions fluxes.

This experimental study assesses the influence of ignition timing on emissions from a production four cylinder port injection spark ignition engine. The aim of this research was to evaluate the necessity of ignition timing correction when the regular gasoline vehicle is being adapted for the use of E85 fuel. Tests were conducted in the Alternative Fuels Research Laboratory of Latvia University of Agriculture in December 2013. The engine was fuelled with the ethanol-gasoline blend E85 or the commercial gasoline A95. The engine was tested within a vehicle in a chassis dynamometer in steady state conditions, which resemble driving at 50 km hE-1 and 90 km hE-1. The original engine control unit was replaced with a programmable one. Engine-out and tailpipe exhaust gas samples were taken and analysed with a FTIR-type analyser AVL SESAM. Carbon monoxide (CO), unburned hydrocarbons (HC), nitrogen oxides (NOx), acetaldehyde and unburned ethanol emission volumetric share is presented. CO, HC and acetaldehyde emissions were not affected by variation of the ignition timing within the tested range. NOx and ethanol emissions were reduced with the ignition timing retard. The emissions of CO, HC and NOx were reduced, when the engine was fuelled with the E85 fuel, comparing with the gasoline use. Ignition timing, optimized for the gasoline, was found suitable for the E85 fuel from the emission analyses point.

The paper contains description of the working principles and evaluation of the operational parameters of the commercially available fuel conversion adapter, intended to adapt gasoline fuelled spark ignition (SI) engine for use of high ethanol content blended fuel, known as E85. Commercially available gasoline and E85 fuel were used as test fuels. Production automobile, equipped with 1.8 litre 4 cylinder SI port fuel injection (PFI) engine was tested on the roll-type eddy-current chassis dynamometer in wide open throttle (WOT) constant speed mode. High precision fuel consumption measurement system AVL KMA Mobile was used. Engine operating parameters, used for evaluation of the efficiency of the fuel conversion adapter was engine torque (T), engine brake power (Pb ), air/fuel equivalence ratio (λ), specific fuel consumption (SFC) and engine thermal efficiency (ηt ). Analysis of engine operational parameters showed successful operation of fuel conversion adapter with E85 fuel, resulting in increase of engine peak torque by 4.4%, increase of energy efficiency in whole tested engine speed range up to 6.1% but increase of specific fuel consumption by approximately 22%, when compared with the gasoline use.

Renewable energy resources play an important role in energy production both in Latvia and in the world. Bio-ethanol is used as a substitute for oil products in various countries of the world. It is produced from the plants containing starch: cereals, potatoes, beet, maize. The task of the research was to evaluate the suitability of different varieties of winter wheat, triticale and rye for extraction of bio-ethanol in Latvia. The research was carried out at the State Stende Cereals Breeding Institute in 2009, and the following varieties and lines of cereals were examined: winter wheat varieties 'Mulan', 'Skalmeje', and the line '99-115', developed at the State Stende Cereals Breeding Institute; winter triticale varieties 'SW Valentino', 'Dinaro', and the line '0002-26', developed at the State Priekuli Plant Breeding Institute; winter rye varieties 'Matador', 'Placido' Fp and 'Dankowskie Nowe'. The content of crude protein and starch of grains, the grain yield, and the bio-ethanol yield were determined. The highest bio-ethanol yield was acquired from the winter wheat and triticale varieties that had the highest starch content and the lowest crude protein content of grains. The best results were obtained from winter wheat line '99-115' and variety 'Mulan' (409.4 and 406.8 L tE-1), triticale variety 'Dinaro' (423.3 L tE-1), and winter rye variety 'Matador' (370.1 L tE-1.).

Plantation willows are commonly grown plants which are widely used for energetic purposes that does not correspond completely to its potential. To fully integrate this resource into biorefinery scheme, it is necessary to study optimal conditions of willow bark processing, aimed for separation of bark components, their comprehensive characterization and profitable practical application. Extraction of secondary metabolites is well known approach for bark processing. But the separation of the main cell wall components including lignin from the residual biomass is less studied. In this work plantation residual willow bark after extractives separation by two different solvents (acetone and ethanolwater) was used as a feedstock for Organosolv delignification. Effect of temperature and catalyst used on the yield and properties of lignin isolated from residual bark by ethanol-water treatment was studied. It was possible to obtain pure lignin with high yields (up to 41%) that has the potential to be used for bio-plastic producing. Insoluble residue after delignification was carbohydrate rich (up to 80%) feedstock allowing its practical use for bioethanol producing.