Fluctuating market price of fossil fuel and overwhelming emission of greenhouse gases to the atmosphere have resulted in climate change and have been a global concern in this decade. Hence, biodiesel has become an alt...Fluctuating market price of fossil fuel and overwhelming emission of greenhouse gases to the atmosphere have resulted in climate change and have been a global concern in this decade. Hence, biodiesel has become an alternative option to fossil diesel as it is renewable and environmentally friendly. Nevertheless, this alternative fuel that is usually derived from terrestrial oil crops will cause shortage in food supply and deforestation if mass production is realized. In recent years, cultivation of aquatic microorganism(particularly microalgae) to produce biodiesel is considered as a practical solution due to their high growth rate and ability to synthesize large quantity of lipid within their cell. However, the development of energy and cost-efficiency of microalgae cultivation system are the main issues in producing renewable microalgae biodiesel. Of late, wastewater or organic compost has been used as the cultivation medium as it can provide sufficient nutrients to sustain microalgae growth.Microalgae cultivation method and system are vitally important as these factors undoubtedly affect the final microalgae biomass and lipid yield. In this review, the cultivation system of microalgae, nutrients demanded for microalgae production, cell harvesting and drying, microalgae oil extraction, and utilization of microalgae biomass for biodiesel production are introduced and discussed. It is anticipated to convey clearer perspectives in upstream and downstream processes in microalgae-derived biodiesel production.展开更多
Objective:A natural cyclic peptide previously isolated from Citrus medica was synthesized by coupling of tetrapep-tide units Boc-Leu-Pro-Trp-Leu-OMe and Boc-Ile-Ala-Ala-Gly-OMe after proper deprotection at carboxyl an...Objective:A natural cyclic peptide previously isolated from Citrus medica was synthesized by coupling of tetrapep-tide units Boc-Leu-Pro-Trp-Leu-OMe and Boc-Ile-Ala-Ala-Gly-OMe after proper deprotection at carboxyl and amino terminals followed by cyclization of linear octapeptide segment. Methods:Solution phase technique was adopted for the synthesis of cyclooctapeptide-sarcodactylamide. Required tetrapeptide units were prepared by coupling of Boc-protected dipeptides viz. Boc-Leu-Pro-OH and Boc-Ile-Ala-OH with respective dipeptide methyl esters Trp-Leu-OMe and Ala-Gly-OMe. Cyclization of linear octapeptide unit was done by p-nitrophenyl ester method. The structure of synthesized cyclopolypeptide was elucidated by FTIR,1H NMR,13C NMR,FABMS spectral data and elemental analysis. The newly synthesized peptide was evaluated for dif-ferent pharmacological activities including antimicrobial,anthelmintic and cytotoxic activities. Results:Synthesis of sarcodac-tylamide was accomplished with >78% yield utilizing dicyclohexylcarbodiimide(DCC) as coupling agent. Newly synthesized peptide possessed potent cytotoxic activity against Dalton's lymphoma ascites(DLA) and Ehrlich's ascites carcinoma(EAC) cell lines,in addition to moderate anthelmintic activity against earthworms Megascoplex konkanensis,Pontoscotex corethruses and Eudrilus sp. Moreover,cyclopolypeptide displayed good antimicrobial activity against pathogenic fungi Candida albicans and Gram-negative bacteria Pseudomonas aeruginosa,in comparison to standard drugs griseofulvin and ciprofloxacin. Conclusion:Solution phase technique employing DCC and triethylamine(TEA) as base proved to be effective for the synthesis of natural cyclooctapeptide. N-methyl morpholine(NMM) was found to be a better base for the cyclization of linear octapeptide unit in comparison to TEA and pyridine.展开更多
US EPA recently issued the final definition for a renewable fuel establishes rule for the revised Renewable Fuel Standard RFS the compliance for each part of its name： （i） to II （Renewable Fuel Standard）. The mai...US EPA recently issued the final definition for a renewable fuel establishes rule for the revised Renewable Fuel Standard RFS the compliance for each part of its name： （i） to II （Renewable Fuel Standard）. The main be a fuel and （ii） to be produced from renewable biomass. This paper addresses the challenges faced by biomass derived fuels on meeting the specifications of those fuels （gasoline, diesel and heating oil）. Biomass-derived products contain oxygenates, some of which might enhance certain fuel specifications, but some others may have deteriorating effects. On directly derived from biomass pyrolysis have been demonstrated to the basis of available data published in the literature, the fuels be far from the concept of ＂substantially similar＂ transportation fuels. Upgrading is required to convert pyrolysis products into fuels that meet specifications. The economical viability of upgrading still faces confirmation, and imposes several technical challenges for truly attractive cost-effective approaches.展开更多
基金Supported by the Ministry of Higher Education,Malaysia(FRGS with cost center015AB-L25)Universiti Teknologi PETRONAS(YUTP-FRG with cost center 0153AAH46)
文摘Fluctuating market price of fossil fuel and overwhelming emission of greenhouse gases to the atmosphere have resulted in climate change and have been a global concern in this decade. Hence, biodiesel has become an alternative option to fossil diesel as it is renewable and environmentally friendly. Nevertheless, this alternative fuel that is usually derived from terrestrial oil crops will cause shortage in food supply and deforestation if mass production is realized. In recent years, cultivation of aquatic microorganism(particularly microalgae) to produce biodiesel is considered as a practical solution due to their high growth rate and ability to synthesize large quantity of lipid within their cell. However, the development of energy and cost-efficiency of microalgae cultivation system are the main issues in producing renewable microalgae biodiesel. Of late, wastewater or organic compost has been used as the cultivation medium as it can provide sufficient nutrients to sustain microalgae growth.Microalgae cultivation method and system are vitally important as these factors undoubtedly affect the final microalgae biomass and lipid yield. In this review, the cultivation system of microalgae, nutrients demanded for microalgae production, cell harvesting and drying, microalgae oil extraction, and utilization of microalgae biomass for biodiesel production are introduced and discussed. It is anticipated to convey clearer perspectives in upstream and downstream processes in microalgae-derived biodiesel production.
文摘Objective:A natural cyclic peptide previously isolated from Citrus medica was synthesized by coupling of tetrapep-tide units Boc-Leu-Pro-Trp-Leu-OMe and Boc-Ile-Ala-Ala-Gly-OMe after proper deprotection at carboxyl and amino terminals followed by cyclization of linear octapeptide segment. Methods:Solution phase technique was adopted for the synthesis of cyclooctapeptide-sarcodactylamide. Required tetrapeptide units were prepared by coupling of Boc-protected dipeptides viz. Boc-Leu-Pro-OH and Boc-Ile-Ala-OH with respective dipeptide methyl esters Trp-Leu-OMe and Ala-Gly-OMe. Cyclization of linear octapeptide unit was done by p-nitrophenyl ester method. The structure of synthesized cyclopolypeptide was elucidated by FTIR,1H NMR,13C NMR,FABMS spectral data and elemental analysis. The newly synthesized peptide was evaluated for dif-ferent pharmacological activities including antimicrobial,anthelmintic and cytotoxic activities. Results:Synthesis of sarcodac-tylamide was accomplished with >78% yield utilizing dicyclohexylcarbodiimide(DCC) as coupling agent. Newly synthesized peptide possessed potent cytotoxic activity against Dalton's lymphoma ascites(DLA) and Ehrlich's ascites carcinoma(EAC) cell lines,in addition to moderate anthelmintic activity against earthworms Megascoplex konkanensis,Pontoscotex corethruses and Eudrilus sp. Moreover,cyclopolypeptide displayed good antimicrobial activity against pathogenic fungi Candida albicans and Gram-negative bacteria Pseudomonas aeruginosa,in comparison to standard drugs griseofulvin and ciprofloxacin. Conclusion:Solution phase technique employing DCC and triethylamine(TEA) as base proved to be effective for the synthesis of natural cyclooctapeptide. N-methyl morpholine(NMM) was found to be a better base for the cyclization of linear octapeptide unit in comparison to TEA and pyridine.
文摘US EPA recently issued the final definition for a renewable fuel establishes rule for the revised Renewable Fuel Standard RFS the compliance for each part of its name： （i） to II （Renewable Fuel Standard）. The main be a fuel and （ii） to be produced from renewable biomass. This paper addresses the challenges faced by biomass derived fuels on meeting the specifications of those fuels （gasoline, diesel and heating oil）. Biomass-derived products contain oxygenates, some of which might enhance certain fuel specifications, but some others may have deteriorating effects. On directly derived from biomass pyrolysis have been demonstrated to the basis of available data published in the literature, the fuels be far from the concept of ＂substantially similar＂ transportation fuels. Upgrading is required to convert pyrolysis products into fuels that meet specifications. The economical viability of upgrading still faces confirmation, and imposes several technical challenges for truly attractive cost-effective approaches.
