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Applied Biochemistry and Biotechnology: Part A: Enzyme Engineering and Biotechnology (v.123, #1-3)
Assessing the emerging biorefinery sector in Canada by Warren E. Mabee; David J. Gregg; John N. Saddler (pp. 765-778).
The biorefinery is a key concept used in the strategies and visions of many industrial countries. The potential for Canadian biorefineries based on lignocellulosic forest and agricultural residues is examined. The sector is described in terms of research interests, emerging companies, and established corporate interests. It is found that the Canadian biorefining sector currently has an emphasis on specific bioproduct generation, and the process elements required for a true sugar-based process are in the research phase. A Canadian national strategy should focus on increasing forest industry participation, and increasing collaboration with the provinces, particularly in western Canada.
Keywords: Biorefinery; bioproducts; national strategy; lignocellulosic biomass; feedstock
A glycoside flavonoid in kudzu (Pueraria lobata) by Ching S. Lau; Danielle J. Carrier; Robert R. Beitle; Luke R. Howard; Jackson O. Lay Jr.; Rohana Liyanage; Edgar C. Clausen (pp. 783-794).
Kudzu (Pueraria lobata) foliage has been touted as a possible energy crop. High-performance liquid chromatography and mass spectrometry analysis of the methanolic kudzu foliage extracts confirmed the presence of robinin (kaempferol-3-O-robinoside-7-O-rhamnoside). Robinin accounted for 0.65±0.16% (dry basis) of kudzu biomass. Fast performance liquid chromatography (FPLC) was employed to fractionate robinin from the crude extract. The antioxidant capacity of robinin was evaluated by an oxygen radical absorbance capacity (ORAC) assay. The ORAC values of pure standard were compared with those of the extract fractions. One milligram of the FPLC-fractionated robinin generated an ORAC value of 5.15±2.00 μmol/mg of Trolox, whereas 1 mg of pure robinin generated an ORAC value of 12.34±0.45 μmol/mg of Trolox. Because of its antioxidant properties, robinin may be a flavonoid worth extracting prior to energy production.
Keywords: Pueraria lobata ; high-performance liquid chromatography; oxygen radical absorbance capacity; antioxidant; robinin; flavonoids
Characterization of low molecular weight organic acids from beech wood treated in supercritical water by Kei Yoshida; Junko Kusaki; Katsunobu Ehara; Shiro Saka (pp. 795-806).
Japanese beech (Fagus crenata Blume), its cell wall components, and model compounds were treated by supercritical water (380°C, 100 MPa) for 5 s using a batch-type reactor to investigate the production behavior of low molecular weight organic acids. It was found that cellulose and hemicellulose were decomposed to formic acid, pyruvic acid, glycolic acid, acetic acid, and lactic acid, whereas lignin was barely decomposed to such organic acids under the given conditions. However, after prolonged treatment (380°C, 100 MPa, 4 min) of lignin, some organic acids were recovered owing perhaps to the decomposition of the propyl side chain of lignin. It was additionally revealed that the predominant organic acid recovered was acetic acid, which might be derived from the acetyl group of hemicellulose in Japanese beech.
Keywords: Biomass conversion; lignocellulosics; organic acid; supercritical water; Japanese beech
Current status of biodiesel development in Brazil by Luiz Pereira Ramos; Helena Maria Wilhelm (pp. 807-819).
In recent years, the concept of producing biodiesel from renewable lipid sources has regained international attention. In Brazil, a national program was launched in 2002 to evaluate the technical, economic, and environmental competitiveness of biodiesel in relation to the commercially available diesel oil. Several research projects were initiated nationwide to investigate and/or optimize biodiesel production from renewable lipid sources and ethanol derived from sugarcane (ethyl esters). Once implemented, this program will not only decrease our dependence on petroleum derivatives but also create new market opportunities for agribusiness, opening new jobs in the countryside, improving the sustainability of our energy matrix, and helping the Brazilian government to support important actions against poverty. This article discusses the efforts to develop the Brazilian biodiesel program in the context of technical specifications as well as potential oilseed sources.
Keywords: Renewable energy; biodiesel; ethyl esters; monoalkyl esters; alcoholysis
Integrated processes for use of pulps and lignins obtained from sugarcane bagasse and straw by Adilson R. Gonçalves; Priscila Benar; Sirlene M. Costa; Denise S. Ruzene; Regina Y. Moriya; Sandra M. Luz; Lais P. Ferretti (pp. 821-826).
Sugarcane bagasse and straw can be converted into pulps, oils, controlled-release formulations, chelating agents, and composites. This article reviews bagasse and straw conversion efforts in Brazil. Laboratory-scale processes were developed aiming at the integral use of these biomass byproducts. Organosolv pulping and oxidation of lignin are the most promising processes for the rational use of sugarcane residues. Fungal pretreatment and spectroscopic characterization are also discussed.
Keywords: Integrated processes; sugarcane bagasse; lignocellulosic residues; Organosolv pulping; biomass pretreatment; spectroscopic characterization
Simultaneous biocatalyst production and baeyer-villiger oxidation for bioonversion of cyclohexanone by recombinant Escherichia coli expressing cyclohexanone monooxygenase by Won-Heong Lee; Yong-Cheol Park; Dae-Hee Lee; Kyungmoon Park; Jin-Ho Seo (pp. 827-836).
Cyclohexanone monooxygenase (CHMO) catalyzing Baeyer-Villiger oxidation converts cyclic ketones into optically pure lactones, which have been used as building blocks in organic synthesis. A recombinant Escherichia coli BL21(DE3)/pMM4 expressing CHMO originated from Acinetobacter sp. NCIB 9871 was used to produce ε-caprolactone through a simultaneous biocatalyst production and Baeyer-Villiger oxidation (SPO) process. Afed-batch process was designed to obtain high cell density for improvin production of ε-caprolactone. The fed-batch SPO process have the best results, 10.2 g/L of ε-caprolactone and 0.34 g/(L·h) of productivity, corresponding to a 10.5- and 3.4-fold enhancement compared with those of the batch SPO, respectively.
Keywords: Simultaneous biocatalyst production and Baeyer-Villiger oxidation; cyclohexanone monooxygenase; Escherichia coli ; fed-batch process; ε-caprolactone
Biotransformation of (−)β-pinene by Aspergillus niger ATCC 9642 by Geciane Toniazzo; Débora de Oliveira; Cláudio Dariva; Enrique Guillermo Oestreicher; Octávio A. C. Antunes (pp. 837-844).
The main objective of this work was to investigate the biotransformations of (−)α-pinene, (−)β-pinene, and (+) limonene by Aspergillus niger ATCC 9642. The culture conditions involved—concentration of cosolvent (EtOH), substrate applied, and sequential addition of substrates—were investigated. Adaptation of the precultures with small amounts of substrate was also studied. The experiments were performed in conical flasks with liquid cultures. This strain of A. niger was able to convert only (−)β-pinene into α-terpineol. An optimum conversion of (−)β-pinene into α-terpineol of about 4% was obtained when the substrate was applied as a diluted solution in EtOH and sequential addition of substrate was used.
Keywords: Biotransformation; β-pinene; α-terpineol; flavors; Aspergillus niger
Characterization of Sol-gel bioencapsulates for ester hydrolysis and synthesis by Cleide M. F. Soares; Heizir F. de Castro; Juliana E. Itako; Flavio F. De Moraes; Gisella M. Zanin (pp. 845-859).
Candida rugosa lipase was entrapped in silica sol-gel particles prepared by hydrolysis of methyltrimethoxysilane and assayed by p-nitrophenyl palmitate hydrolysis, as a function of pH and temperature, giving pH optima of 7.8 (free enzyme) and 5.0–8.0 (immobilized enzyme). The optimum temperature for the immobilized enzyme (50–55°C) was 19°C higher than for the free enzyme. Thermal, operational, and storage stability were determined with n-butanol and bytyric acid, giving at 45°C a half-life 2.7 times greater for the immobilized enzyme; storage time was 21 d at room temperature. For ester synthesis, the optimum temperature was 47°C, and high esterification conversions were obtained under repeated batch cycles (half-life of 138 h).
Keywords: Thermal stability; sol-gel; immobilization; lipase; encapsulation
Culture medium optimization for acetic acid production by a persimmon vinegar-derived bacterium by Jin-Nam Kim; Jong-Sok Choo; Young-Jung Wee; Jong-Sun Yun; Hwa-Won Ryu (pp. 861-869).
A new acetic acid-producing microorganism, Acetobacter sp. RKY4, was isolated from Korean traditional persimmon vinegar, and we optimized the culture medium for acetic acid production from ethanol using the newly isolated Acetobacter sp. RKY4. The optimized culture medium for acetic acid production using this microorganism was found to be 40 g/L ethanol, 10 g/L glycerol, 10 g/L corn steep liquor, 0.5 g/L MgSO4·7H2O, and 1.0 g/L (NH4H2PO4. Acetobacter sp. RKY4 produced 47.1 g/L of acetic acid after 48 h of fermentation in a 250 mL Erlenmeyer flask containing 50 mL of the optimized medium.
Keywords: Acetobacter sp. RKY4; acetic acid; ethanol; persimmon vinegar
The lignol approach to biorefining of woody biomass to produce ethanol and chemicals by Claudio Arato; E. Kendall Pye; Gordon Gjennestad (pp. 871-882).
Processes that produce only ethanol from lignocellulosics display poor economics. This is generally overcome by constructing large facilities having satisfactory economies of scale, thus making financing onerous and hindering the development of suitable technologies. Lignol Innovations has developed a biorefining technology that employs an ethanol-based organosolv step to separate lignin, hemicellulose components, and extractives from the cellulosic fraction of woody biomass. The resultant cellulosic fraction is highly susceptible to enzymatic hydrolysis, generating very high yields of glucose (>90% in 12–24h) with typical enzyme loadings of 10–20 FPU (filter paper units)/g. This glucose is readily converted to ethanol, or possibly other sugar platform chemicals, either by sequential or simultaneous saccharification and fermentation. The liquor from the organosolv step is processed by well-established unit operations to recover lignin, furfural, xylose, acetic acid, and a lipophylic extractives fraction. The process ethanol is recovered and recycled back to the process. The resulting recycled process water is of a very high quality, low BOD5, and suitable for overall system process closure. Significant benefits can be attained in greenhouse gas (GHG) emission reductions, as per the Kyoto Protocol. Revenues from the multiple products, particularly the lignin, ethanol and xylose fractions, ensure excellent economics for the process even in plants as small as 100 mtpd (metric tonnes per day) dry woody biomass input—a scale suitable for processing wood residues produced by a single large sawmill.
Keywords: Lignol; biorefinery; wood; ethanol