Quantitative proteomics analysis of an ethanol- and a lactate-producing mutant strain of Synechocystis sp. PCC6803

BACKGROUND: This study aimed at exploring the molecular physiological consequences of a major redirection of carbon flow in so-called cyanobacterial cell factories: quantitative whole-cell proteomics analyses were carried out on two (14)N-labelled Synechocystis mutant strains, relative to their (15)N-labelled wild-type counterpart. Each mutant strain overproduced one specific commodity product, i.e. ethanol or lactic acid, to such an extent that the majority of the incoming CO2 in the organism was directly converted into the product. RESULTS: In total, 267 proteins have been identified with a significantly up- or down-regulated expression level. In the ethanol-producing mutant, which had the highest relative direct flux of carbon-to-product (>65%), significant up-regulation of several components involved in the initial stages of CO2 fixation for cellular metabolism was detected. Also a general decrease in abundance of the protein synthesizing machinery of the cells and a specific induction of an oxidative stress response were observed in this mutant. In the lactic acid overproducing mutant, that expresses part of the heterologous l-lactate dehydrogenase from a self-replicating plasmid, specific activation of two CRISPR associated proteins, encoded on the endogenous pSYSA plasmid, was observed. RT-qPCR was used to measure, of nine of the genes identified in the proteomics studies, also the adjustment of the corresponding mRNA level. CONCLUSION: The most striking adjustments detected in the proteome of the engineered cells were dependent on the specific product formed, with, e.g. more stress caused by lactic acid- than by ethanol production. Up-regulation of the total capacity for CO2 fixation in the ethanol-producing strain was due to hierarchical- rather than metabolic regulation. Furthermore, plasmid-based expression of heterologous gene(s) may induce genetic instability. For selected, limited, number of genes a striking correlation between the respective mRNA- and the corresponding protein expression level was observed, suggesting that for the expression of these genes regulation takes place primarily at the level of gene transcription

Prospects of biodiesel from Jatropha in Malaysia

The increasing energy demands along with the expected depletion of fossil fuels have promoted to search for alternative fuels that can be obtained from renewable energy resources. Biodiesel as a renewable energy resource has drawn the attention of many researchers and scientists because its immense potential to be part of a sustainable energy mix in near future. This report attempts to compile the findings on current global and Malaysian energy scenario, potential of biodiesel as a renewable energy source, biodiesel policies and standards, practicability of Jatropha curcas as a biodiesel source in Malaysia as well as impact of biodiesel from Jatropha curcas. Final part of this report also describes the development of biodiesel market in Malaysia. The paper found that Jatropha curcas is one of the cheapest biodiesel feedstock and it possesses the amicable fuel properties with higher oil contents compared to others. Being non edible oil seed feedstocks it will not affect food price and spur the food versus fuel dispute. Jatropha can be substituted significantly for oil imports. Jatropha biodiesel has potential to reduce GHG emission than diesel fuel and it can be used in diesel engine with similar performance of diesel fuel. Jatropha curcas has an immense contribution to develop rural livelihoods too. Finally biodiesel production from Jatropha is eco-friendly and offers many social and economical benefits for Malaysia and can play an increasingly significant role to fulfill the energy demand in Malaysia.Associated Grant:The authors would like to acknowledge University of Malaya for financial support through High Impact Research Grant entitles: Clean Diesel Technology for Military and Civilian Transport Vehicles which Grant number is UM.C/HIR/MOHE/ENG/07

An overview on comparative engine performance and emission characteristics of different techniques involved in diesel engine as dual-fuel engine operation

Abatement of pollutant emissions from transport sector is one of the major concerns throughout the globe. One of the main technical challenges for transportation sector is to reduce pollutant emissions from diesel engine and to meet satisfactory engine performance, simultaneously. Different technical changes have been introduced in diesel engine to apply alternative biofuels to reduce pollutant emissions. Blend, fumigation, and emulsion are three different dual fuel engine operation techniques, which have been introduced in diesel engine for biofuel application. In the blend mode, biofuel and diesel are mixed in desired proportions before injecting into cylinder, whereas in fumigation mode, biofuel is injected into intake manifold to mix with the intake fresh air. Emulsion is a process wherein two immiscible substances are mixed together. This study provides a comprehensive review on these three techniques of biofuel injection and their comparative effects on the engine performance and emissions. From these studies, it is found that the effects on engine performance and emission mostly depend on biofuel properties. Increase in break specific fuel consumption (BSFC) is common in each method due to the lower calorific value of biofuels. Brake thermal efficiency (BTE) decreases in blend and fumigation modes, but increases in emulsion mode. Nitrogen oxides (NOx) emissions decrease in fumigation and emulsion modes, but increase in blend mode. Carbon monoxide (CO) and Hydro carbon (HC) emissions increase in fumigation and emulsion modes, but decrease in blend mode. Particulate Matter (PM) emission decreases in all three modes

Effects of biodiesel blends on lubricating oil degradation and piston assembly energy losses

Fuel is considered a major influencing parameter for engine oil condition during extended engine operation. Its effects on engine oil performance is required to be investigated with the implementation of the worldwide biodiesel mandate in various countries. This research monitored the influence of biodiesel on the condition of engine lube oil by long duration testing on three fuels: DF as the baseline; 20% palm biodiesel and 80% DF (PB20); and 20% jatropha biodiesel and 80% DF (JB20). The tests were carried out on a single-cylinder CI engine. Sump oil samples were collected at regular intervals during 200-h tests, after which the rheological, tribological, and chemical properties of the samples were investigated. Results showed that the B20 fuels decreased the viscosity and increased the acidity of the engine oil. Piston ring-cylinder and piston skirt-cylinder tests, in which a high-stroke reciprocating test rig was used, showed a slight increase in friction and wear losses near the intervals of oil draining for the B20 fuels. Chemical analysis by Fourier transform infrared spectroscopy and ASTM standard testing showed a decrease in soot loading but an increase in the fuel residue, corrosiveness, and oxidation of the engine oil samples for B20 fuelled engine tests

Application of blend fuels in a diesel engine

Experimental study has been carried out to analyze engine performance and emissions characteristics for diesel engine using different blend fuels without any engine modifications. A total of four fuel samples, such as DF (100% diesel fuel), JB5 (5% jatropha biodiesel and 95% DF), JB10 (10% JB and 90% DF) and J5W5 (5% JB, 5% waste cooking oil and 90% DF) respectively were used in this study. Engine performance test was carried out at 100% load keeping throttle 100% wide open with variable speeds of 1500 to 2400 rpm at an interval of 100 rpm. Whereas, emission tests were carried out at 2300 rpm at 100% and 80% throttle position. As results of investigations, the average torque reduction compared to DF for JB5, JB10 and J5W5 was found as 0.63%, 1.63% and 1.44% and average power reduction was found as 0.67%, 1.66% and 1.54% respectively. Average increase in bsfc compared to DF was observed as 0.54%, 1.0% JB10 and 1.14% for JB5, JB10 and J5W5 respectively. In case of engine exhaust gas emissions, compared to DF average reduction in HC for JB5, JB10 and J5W5 at 2300 rpm and 100% throttle position found as 8.96%, 11.25% and 12.50%, whereas, at 2300 and 80% throttle position, reduction was as 16.28%, 30.23% and 31.98% respectively. Average reduction in CO at 2300 rpm and 100% throttle position for JB5, JB10 and J5W5 was found as 17.26%, 25.92% and 26.87%, whereas, at 80% throttle position, reduction was observed as 20.70%, 33.24% and 35.57%. Similarly, the reduction in CO2 compared to DF for JB5, JB10 and J5W5 at 2300 rpm and 100% throttle position was as 12.10%, 20.51% and 24.91%, whereas, at 80% throttle position, reductions was observed as 5.98%, 10.38% and 18.49% respectively. However, some NOx emissions were increased for all blend fuels compared to DF. In case of noise emission, sound level for all blend fuels was reduced compared to DF. It can be concluded that JB5, JB10 and J5W5 can be used in diesel engines without any engine modifications However, W5B5 produced some better results when compared to JB10. © 2011 Published by Elsevier Ltd

Prospects of biodiesel from Jatropha in Malaysia

The increasing energy demands along with the expected depletion of fossil fuels have promoted to search for alternative fuels that can be obtained from renewable energy resources. Biodiesel as a renewable energy resource has drawn the attention of many researchers and scientists because its immense potential to be part of a sustainable energy mix in near future. This report attempts to compile the findings on current global and Malaysian energy scenario, potential of biodiesel as a renewable energy source, biodiesel policies and standards, practicability of Jatropha curcas as a biodiesel source in Malaysia as well as impact of biodiesel from Jatropha curcas. Final part of this report also describes the development of biodiesel market in Malaysia. The paper found that Jatropha curcas is one of the cheapest biodiesel feedstock and it possesses the amicable fuel properties with higher oil contents compared to others. Being non edible oil seed feedstocks it will not affect food price and spur the food versus fuel dispute. Jatropha can be substituted significantly for oil imports. Jatropha biodiesel has potential to reduce GHG emission than diesel fuel and it can be used in diesel engine with similar performance of diesel fuel. Jatropha curcas has an immense contribution to develop rural livelihoods too. Finally biodiesel production from Jatropha is eco-friendly and offers many social and economical benefits for Malaysia and can play an increasingly significant role to fulfill the energy demand in Malaysia

Effect of coconut biodiesel blended fuels on engine performance and emission characteristics

Alternative fuels have received much attention due to the depletion of world petroleum reserves and increased environmental concerns. Thus processed form of vegetable oil (Biodiesel) offers attractive alternative fuels to compression ignition engines. The present work investigates the engine performance parameters and emissions characteristics for direct injection diesel engine using coconut biodiesel blends without any engine modifications. A total of three fuel samples, such as DF (100% diesel fuel), CB5 (5% coconut biodiesel and 95% DF), and CB15 (15% CB and 85% DF) respectively are used. Engine performance test has been carried out at 100% load, keeping throttle 100% wide open with variable speeds of 1500 to 2400 rpm at an interval of 100 rpm. Whereas, engine emission tests have been carried out at 2200 rpm at 100% and 80% throttle position. As results of investigations, there has been a decrease in torque and brake power, while increase in specific fuel consumption has been observed for biodiesel blended fuels over the entire speed range compared to net diesel fuel. In case of engine exhaust gas emissions, lower HC, CO and, higher CO2 and NOx emissions have been found for biodiesel blended fuels compared to diesel fuel. Moreover, reduction in sound level for both biodiesel blended fuels has been observed when compared to diesel fuel. Therefore, it can be concluded that CB5 and CB15 can be used in diesel engines without any engine modifications and have beneficial effects both in terms of emission reductions and alternative petroleum diesel fuel. © 2013 The Authors. Published by Elsevier Ltd

Effect of coconut biodiesel blended fuels on engine performance and emission characteristics

Alternative fuels have received much attention due to the depletion of world petroleum reserves and increased environmental concerns. Thus processed form of vegetable oil (Biodiesel) offers attractive alternative fuels to compression ignition engines. The present work investigates the engine performance parameters and emissions characteristics for direct injection diesel engine using coconut biodiesel blends without any engine modifications. A total of three fuel samples, such as DF (100% diesel fuel), CB5 (5% coconut biodiesel and 95% DF), and CB15 (15% CB and 85% DF) respectively are used. Engine performance test has been carried out at 100% load, keeping throttle 100% wide open with variable speeds of 1500 to 2400 rpm at an interval of 100 rpm. Whereas, engine emission tests have been carried out at 2200 rpm at 100% and 80% throttle position. As results of investigations, there has been a decrease in torque and brake power, while increase in specific fuel consumption has been observed for biodiesel blended fuels over the entire speed range compared to net diesel fuel. In case of engine exhaust gas emissions, lower HC, CO and, higher CO2 and NOx emissions have been found for biodiesel blended fuels compared to diesel fuel. Moreover, reduction in sound level for both biodiesel blended fuels has been observed when compared to diesel fuel. Therefore, it can be concluded that CB5 and CB15 can be used in diesel engines without any engine modifications and have beneficial effects both in terms of emission reductions and alternative petroleum diesel fuel. © 2013 The Authors. Published by Elsevier Ltd