Dilip K. Adhikari

Effective catalytic conversion of cellulose into high yields of methyl glucosides over sulfonated carbon based catalyst.

An amorphous carbon based catalyst was prepared by sulfonation of the bio-char obtained from fast pyrolysis (N(2) atm; ≈ 550°C) of biomass. The sulfonated carbon catalyst contained high acidity of 6.28 mmol/g as determined by temperature programmed desorption of ammonia of sulfonated carbon catalyst and exhibited high catalytic performance for the hydrolysis of cellulose. Amorphous carbon based catalyst containing -SO(3)H groups was successfully tested and the complete conversion of cellulose in methanol at moderate temperatures with high yields ca. ≥ 90% of α, β-methyl glucosides in short reaction times was achieved. The methyl glucosides formed in methanol are more stable for further conversion than the products formed in water. The carbon catalyst was demonstrated to be stable for five cycles with slight loss in catalytic activity. The utilization of bio-char as a sulfonated carbon catalyst provides a green and efficient process for cellulose conversion.

Bioemulsifier production by an oleaginous yeastRhodotorulaglutinis IIP-30

SummaryA locally isolated oleaginous strain ofRhodotorulaglutinis strain IIP-30 produced a growth associated extracellular emulsifying agent while utilizing glucose during fed batch fermentation under nitrogen limitation at 30°C and pH 4. 0. Similar optimum conditions were also noted for intracellular lipid accumulation.

Production of bioemulsifier by a SCP-producing strain ofCandida tropicalis during hydrocarbon fermentation

SummarySCP producingCandida tropicalis, when grown in fed batch culture using n-hexadecane as carbon substrate, exhibited extracellular emulsifier production. The emulsifier showed activity against various hydrocarbons, maximum with aromatics and least with normal paraffins. Higher emulsification activity was noted in nitrogen-limiting growth conditions than in substrate- limiting conditions. The hot water extract of the cells also showed significant emulsification activity.

Utilization of molasses for the production of fat by an oleaginous yeast,Rhodotorula glutinis IIP-30

SummaryRhodotorula glutinis is known to produce fat when cultivated under nitrogen-limiting conditions. Economically, molasses is an ideal substrate, however, due to the presence of nitrogen in molasses, the lipid yield obtained is much lower than that obtained from glucose or sucrose. Higher yields were obtained using molasses in a fed batch fermentation supplemented with glucose or sucrose during the lipid accumulation phase. The fatty acids profile of the lipids thus produced, using a very simple and economical medium, was similar to that obtained from glucose and sucrose.

Catalytic cracking of jatropha-derived fast pyrolysis oils with VGO and their NMR characterization

Lignocellulosic biomass-derived fast pyrolysis oils are potential second-generation bio-fuels towards the reduction of greenhouse gas (GHG) emissions and carbon foot prints. This study pertains to co-process the Jatropha-derived heavy or tar fraction of fast pyrolysis oil (FPO) with vacuum gas oil (VGO) and hydrodeoxygenated fast pyrolysis oil (HDO) with VGO in a standard refinery fluid catalytic cracking (FCC) unit. The crude fast pyrolysis oil from Jatropha curcas is produced at 530 °C and atmospheric pressure using a bubbling fluidized bed pyrolyzer. The heavy fraction of FPO is hydrodeoxygenated over Pd/Al2O3 catalyst into HDO in an autoclave reactor at 300 °C and pressure of 80 bar. Further, HDO is co-processed with petroleum-derived VGO in an advanced cracking evaluation (ACE-R) unit to convert it into refinery FCC product slate hydrocarbons at a blending ratio of 5 : 95. FPO and HDO are characterized using 31P NMR, whereas FCC distillates, which are obtained on the co-processing of VGO with fast pyrolysis oil and HDO, are characterized using 1H and 13C NMR spectroscopy techniques. The 31P NMR analysis of crude FPO and HDO indicated that hydroxyl, carboxylic and methoxy groups are reduced during the hydrodeoxygenation of FPO. The experimental results at the iso-conversion level on the co-processing of HDO with VGO indicated a higher yield of liquefied petroleum gases (LPG), while lower yields of gasoline and LCO have been observed as compared to FPO co-processing with VGO and co-processing of pure VGO. Furthermore, the results of co-processing of FPO with VGO indicated that the yields of gasoline and LCO increased from 29 to 35 wt% and 14.8 to 20.4 wt%, respectively, whereas the yields of dry gas and LPG decreased from 2.1 to 1.4 wt% and 38.8 to 23.7 wt%, respectively, for an increase in the blending ratio from 5% to 20%. Therefore, it can be concluded that the co-processing of HDO with VGO in a FCC unit would be feasible in order to achieve a higher yield of LPG.

Feasibility of ethanol production with enhanced sugar concentration in bagasse hydrolysate at high temperature using Kluyveromyces sp. IIPE453

Background: Ethanol from lignocellulosic biomass and nonfood sources has caught worldwide attention because of its potential use as an alternative automotive fuel. Results: In batch fermentation using Kluyveromyces sp. IIPE453 at 50°C on bagasse hydrolysate containing total fermenting sugar concentration 35 ±1.9 g l-1, the strain could produce ethanol concentration 14.5 ± 0.2 g l-1 with ethanol productivity 0.71 ± 0.001 g l-1 h-1 as compared with sugarcane juice 2 ± 0.04 g l-1 h-1, molasses 2.6 ± 0.05 g l-1 h-1 and mahua flower extract 3.4 ± 0.06 g l-1 h-1. In addition, the fermentation was carried out with enhanced sugar concentration in bagasse hydrolysate by mixing sugarcane juice, molasses and extract of mahua flowers. The ethanol productivities upon mixture of bagasse hydrolysate with sugarcane juice, molasses and extract of mahua flowers were 1.7 ± 0.06 g l-1 h-1, 1.75 ± 0.03 g l-1 h-1 and 2.57 ± 0.1 g l-1 h-1, respectively. Conclusion: The ethanol productivity could be increased by enhancing sugar concentration in bagasse hydrolysate. The product inhibition could be minimized by in situ ethanol recovery at high temperature.

Lignocellulosic sugar management for xylitol and ethanol fermentation with multiple cell recycling by Kluyveromyces marxianus IIPE453

Optimum utilization of fermentable sugars from lignocellulosic biomass to deliver multiple products under biorefinery concept has been reported in this work. Alcohol fermentation has been carried out with multiple cell recycling of Kluyveromyces marxianus IIPE453. The yeast utilized xylose-rich fraction from acid and steam treated biomass for cell generation and xylitol production with an average yield of 0.315±0.01g/g while the entire glucose rich saccharified fraction had been fermented to ethanol with high productivity of 0.9±0.08g/L/h. A detailed insight into its genome illustrated the strains complete set of genes associated with sugar transport and metabolism for high-temperature fermentation. A set flocculation proteins were identified that aided in high cell recovery in successive fermentation cycles to achieve alcohols with high productivity. We have brought biomass derived sugars, yeast cell biomass generation, and ethanol and xylitol fermentation in one platform and validated the overall material balance. 2kg sugarcane bagasse yielded 193.4g yeast cell, and with multiple times cell recycling generated 125.56g xylitol and 289.2g ethanol (366mL).

High-level expression, purification and characterization of carbazole dioxygenase, a three components dioxygenase, of Pseudomonas GBS.5

ObjectiveTo investigate the conversion of carbazole into 2′-aminobiphenyl-2,3-diol using carbazole dioxygenase (CARDO) that is a multicomponent enzyme consisting of homotrimeric terminal oxygenases (CarAa), a ferredoxin (CarAc) and a ferredoxin reductase (CarAd) unit, encoded by the carAa, carAc and carAd genes, respectively.ResultsThe enzyme subunits containing a GST tag were expressed independently in E. coli. The expressed proteins were purified by one-step immobilized affinity chromatography and three purified proteins could reconstitute the CARDO activity in vitro and showed activity against carbazole as well as against wide range of polyaromatic compounds.ConclusionThis method provides an efficient way to obtain an active carbazole dioxygenase with high yield, high purity and with activity against a wide range of polyaromatic compounds.

Dibenzothiophene desulfurization in hydrocarbon environment by Staphylococcus sp. resting cells

Staphylococcus sp. strain S3/C desulfurized dibenzothiophene/n-hexadecane (3 mg ml−1) in a hydrocarbon aqueous biphasic culture. The resting cells decreased the sulfur content of the hydrocarbon phase by 57% at 2.2 mg l−1 h−1 in the absence of any additional carbon and sulfur source.

Bio-jet Fuel

The crude oils are processed in a refinery to make a host of useful products; including gasoline, diesel, jet fuel, petrochemicals, and asphalt components. Kerosene is produced as a straight run product but is also produced through hydroprocesses, especially from heavier crude oil feedstocks. Kerosene jet fuel is a hydrocarbon fuel composed almost entirely of hydrogen and carbon elements. The hydrocarbon composition consists mainly of paraffins (iso and normal), cycloparaffins (naphthenes), and aromatics. Aviation jet fuel produced from different feeds and processes will have different ratios of these hydrocarbon components. Combustion of Aviation Turbine fuel or jet fuel (Jet-A1) for aviation purpose has contributed to “global warming” leading to a proposed blending of “Biojet” to reduce the carbon footprint. In 2009 a new ASTM specification (D7566-09, Standard Specification for Aviation Turbine Fuel Containing Synthesized Hydrocarbons) was developed for aviation turbine fuels. The specification allows for a maximum of a 50% blend of Biojet with conventional jet fuel. While Bioethanol and Biobutanol, a proven biofuel for the automobiles, were found unsuitable biofuel for aviation purpose due to a mismatch in ASTM D7566-09 specifications. Several technological options have emerged on intensive R&D efforts globally. Such technologies used plant seed oil, waste cooking oil, animal fat, agricultural residues, and MSW as feedstock to produce renewable hydrocarbon fraction as drop-in fuel known as “Biojet”. Basic advantage of using plant or agricultural waste based feedstock instead if crude oil is the minimization of carbon footprint in the aviation fuel. However, several challenges have emerged to meet the stringent specifications of aviation fuel and challenges being addressed to ascertain Biojet as sustainable, cost-effective, and green aviation fuel.