Lipase-catalyzed transesterification of rapeseed oil for biodiesel production with tert-butanol.

Jeong, Gwi-Taek,Park, Don-Hee Humana Press ; Humana Press ; OCLC 2008 Applied biochemistry and biotechnology Vol.148 No.1

<P>Biodiesel is a fatty acid alkyl ester that can be derived from any vegetable oil or animal fat via the process of transesterification. It is a renewable, biodegradable, and nontoxic fuel. In this paper, we have evaluated the efficacy of a transesterification process for rapeseed oil with methanol in the presence of an enzyme and tert-butanol, which is added to ameliorate the negative effects associated with excess methanol. The application of Novozym 435 was determined to catalyze the transesterification process, and a conversion of 76.1% was achieved under selected conditions (reaction temperature 40 degrees C, methanol/oil molar ratio 3:1, 5% (w/w) Novozym 435 based on the oil weight, water content 1% (w/w), and reaction time of 24h). It has also been determined that rapeseed oil can be converted to fatty acid methyl ester using this system, and the results of this study contribute to the body of basic data relevant to the development of continuous enzymatic processes.</P>

Pretreatment characteristics of waste oak wood by ammonia percolation.

Kim, Jun-Seok,Kim, Hyunjoon,Lee, Jin-Suk,Lee, Joon-Pyo,Park, Soon-Chul Humana Press ; Humana Press ; OCLC 2008 Applied biochemistry and biotechnology Vol.148 No.1

<P>A log of waste oak wood collected from a Korean mushroom farm has been tested for ammonia percolation pretreatment. The waste log has different physical characteristics from that of virgin oak wood. The density of the waste wood was 30% lower than that of virgin oak wood. However, there is little difference in the chemical compositions between the woods. Due to the difference in physical characteristics, the optimal pretreatment conditions were also quite different. While for waste oak the optimum temperature was determined to be 130 degrees C, for virgin oak wood the optimum pretreatment was only achieved at 170 degrees C. Presoaking for 12 h with ammonia solution before pretreatment was helpful to increase the delignification efficiency.</P>

Production and characterization of biodiesel from tung oil.

Park, Ji-Yeon,Kim, Deog-Keun,Wang, Zhong-Ming,Lu, Pengmei,Park, Soon-Chul,Lee, Jin-Suk Humana Press ; Humana Press ; OCLC 2008 Applied biochemistry and biotechnology Vol.148 No.1

<P>The feasibility of biodiesel production from tung oil was investigated. The esterification reaction of the free fatty acids of tung oil was performed using Amberlyst-15. Optimal molar ratio of methanol to oil was determined to be 7.5:1, and Amberlyst-15 was 20.8 wt% of oil by response surface methodology. Under these reaction conditions, the acid value of tung oil was reduced to 0.72 mg KOH/g. In the range of the molar equivalents of methanol to oil under 5, the esterification was strongly affected by the amount of methanol but not the catalyst. When the molar ratio of methanol to oil was 4.1:1 and Amberlyst-15 was 29.8 wt% of the oil, the acid value decreased to 0.85 mg KOH/g. After the transesterification reaction of pretreated tung oil, the purity of tung biodiesel was 90.2 wt%. The high viscosity of crude tung oil decreased to 9.8mm(2)/s at 40 degrees C. Because of the presence of eleostearic acid, which is a main component of tung oil, the oxidation stability as determined by the Rancimat method was very low, 0.5h, but the cold filter plugging point, -11 degrees C, was good. The distillation process did not improve the fatty acid methyl ester content and the viscosity.</P>

Biodiesel production from various oils under supercritical fluid conditions by Candida antartica lipase B using a stepwise reaction method.

Lee, Jong Ho,Kwon, Cheong Hoon,Kang, Jeong Won,Park, Chulhwan,Tae, Bumseok,Kim, Seung Wook Humana Press ; Humana Press ; OCLC 2009 Applied biochemistry and biotechnology Vol.156 No.1

<P>In this study, we evaluate the effects of various reaction factors, including pressure, temperature, agitation speed, enzyme concentration, and water content to increase biodiesel production. In addition, biodiesel was produced from various oils to establish the optimal enzymatic process of biodiesel production. Optimal conditions were determined to be as follows: pressure 130 bar, temperature 45 degrees C, agitation speed 200 rpm, enzyme concentration 20%, and water contents 10%. Among the various oils used for production, olive oil showed the highest yield (65.18%) upon transesterification. However, when biodiesel was produced using a batch system, biodiesel conversion yield was not increased over 65%; therefore, a stepwise reaction was conducted to increase biodiesel production. When a reaction medium with an initial concentration of methanol of 60 mmol was used and adjusted to maintain this concentration of methanol every 1.5 h during biodiesel production, the conversion yield of biodiesel was 98.92% at 6 h. Finally, reusability was evaluated using immobilized lipase to determine if this method was applicable for industrial biodiesel production. When biodiesel was produced repeatedly, the conversion rate was maintained at over 85% after eight reuses.</P>

Optimization of oligosaccharide synthesis from cellobiose by dextransucrase.

Kim, Misook,Day, Donal F Humana Press ; Humana Press ; OCLC 2008 Applied biochemistry and biotechnology Vol.148 No.1

<P>There is a growing market for oligosaccharides as sweeteners, prebiotics, anticariogenic compounds, and immunostimulating agents in both food and pharmaceutical industries. Interest in novel carbohydrate-based products has grown because of their reduced toxicity and low immune response. Cellobiose is potentially valuable as a nondigestible sugar. The reaction of cellobiose, as an acceptor with a sucrose as a donor, catalyzed by a dextransucrase from Leuconostoc mesenteroides B-512FMCM, produced a series of cellobio-oligosaccharides. This production system was optimized using a Box-Behnken experimental design for 289 mM of sucrose and 250 mM of cellobiose and 54 U of the enzyme at pH 5.2 and 30 degrees C, to produce maximum yields of oligosaccharide.</P>

Hydrolysis of ammonia-pretreated sugar cane bagasse with cellulase, beta-glucosidase, and hemicellulase preparations.

Prior, Bernard A,Day, Donal F Humana Press ; Humana Press ; OCLC 2008 Applied biochemistry and biotechnology Vol.146 No.1

<P>Sugar cane bagasse consists of hemicellulose (24%) and cellulose (38%), and bioconversion of both fractions to ethanol should be considered for a viable process. We have evaluated the hydrolysis of pretreated bagasse with combinations of cellulase, beta-glucosidase, and hemicellulase. Ground bagasse was pretreated either by the AFEX process (2NH(3): 1 biomass, 100 degrees C, 30 min) or with NH(4)OH (0.5 g NH(4)OH of a 28% [v/v] per gram dry biomass; 160 degrees C, 60 min), and composition analysis showed that the glucan and xylan fractions remained largely intact. The enzyme activities of four commercial xylanase preparations and supernatants of four laboratory-grown fungi were determined and evaluated for their ability to boost xylan hydrolysis when added to cellulase and beta-glucosidase (10 filter paper units [FPU]: 20 cellobiase units [CBU]/g glucan). At 1% glucan loading, the commercial enzyme preparations (added at 10% or 50% levels of total protein in the enzyme preparations) boosted xylan and glucan hydrolysis in both pretreated bagasse samples. Xylanase addition at 10% protein level also improved hydrolysis of xylan and glucan fractions up to 10% glucan loading (28% solids loading). Significant xylanase activity in enzyme cocktails appears to be required for improving hydrolysis of both glucan and xylan fractions of ammonia pretreated sugar cane bagasse.</P>

Optimization of biodiesel production from castor oil using response surface methodology.

Jeong, Gwi-Taek,Park, Don-Hee Humana Press ; Humana Press ; OCLC 2009 Applied biochemistry and biotechnology Vol.156 No.1

<P>The short supply of edible vegetable oils is the limiting factor in the progression of biodiesel technology; thus, in this study, we applied response surface methodology in order to optimize the reaction factors for biodiesel synthesis from inedible castor oil. Specifically, we evaluated the effects of multiple parameters and their reciprocal interactions using a five-level three-factor design. In a total of 20 individual experiments, we optimized the reaction temperature, oil-to-methanol molar ratio, and quantity of catalyst. Our model equation predicted that the following conditions would generate the maximum quantity of castor biodiesel (92 wt.%): a 40-min reaction at 35.5 degrees C, with an oil-to-methanol molar ratio of 1:8.24, and a catalyst concentration of 1.45% of KOH by weight of castor oil. Subsequent empirical analyses of the biodiesel generated under the predicted conditions showed that the model equation accurately predicted castor biodiesel yields within the tested ranges. The biodiesel produced from castor oil satisfied the relevant quality standards without regard to viscosity and cold filter plugging point.</P>

Mobilization and biodegradation of 2-methylnaphthalene by amphiphilic polyurethane nano-particle.

Kim, Young-Bum,Kim, Ju-Young,Kim, Eun-ki Humana Press ; Humana Press ; OCLC 2009 Applied biochemistry and biotechnology Vol.159 No.1

<P>Amphiphilic polyurethane (APU) nano-particle enhanced the mobilization of 2-methylnaphthalene (2-MNPT) in soil. Significant increase in the solubility of 2-MNPT was achieved. The molar solubilization ratio was 0.4 (mole 2-MNPT/mole APU). Simple precipitation of APU particle by 2 N CaCl(2) recovered 95% of APU particle and 92% of 2-MNPT simultaneously. Also, 2-MNPT, which was entrapped inside the APU particle, was directly degraded by Acinetobacter sp. as same efficiency as without APU particle. These results showed the potentials of APU particle in the mobilization and biodegradation of hydrophobic compounds from soil.</P>

Tagatose production with pH control in a stirred tank reactor containing immobilized L-arabinose rom Thermotoga neapolitana.

Lim, Byung-Chul,Kim, Hye-Jung,Oh, Deok-Kun Humana Press ; Humana Press ; OCLC 2008 Applied biochemistry and biotechnology Vol.149 No.3

<P>Chitopearl beads were used as immobilization supports for D-tagatose production from D-galactose by L-arabinose isomerase from Thermotoga neapolitana because chitopearl beads were more stable than alginate beads at temperatures above 60 degrees C. The pH and temperature for the maximum isomerization of galactose were 7.5 and 90 degrees C, respectively. In thermostability experiments, the half-lives of the immobilized enzyme at 70, 75, 80, 85, and 90 degrees C were 388, 106, 54, 36, and 22 h, respectively. The reaction temperature was determined to be 70 degrees C because the enzyme is highly stable up to 70 degrees C during the reaction. When the reaction time, galactose concentration, and temperature were increased, the pH of a mixture containing enzyme and galactose decreased by the Maillard reaction, resulting in decreased tagatose production. With pH control at 7.5, tagatose production (138 g/L) at 70 degrees C in a stirred tank reactor containing immobilized enzyme and 300 g/L galactose increased two times higher, comparing that without pH control.</P>

Culture pH affects exopolysaccharide production in submerged mycelial culture of Ganoderma lucidum.

Kim, Hyun Mi,Park, Moon Ki,Yun, Jong Won Humana Press ; Humana Press ; OCLC 2006 Applied biochemistry and biotechnology Vol.134 No.3

<P>In submerged culture of Ganoderma lucidum, the pH optimum for cell growth has been shown to be lower than that for exopolysaccharides (EPS) formation. Therefore, in the present study, a two-stage pH-control strategy was employed to maximize the productions of mycelial biomass and EPS. When compared, a batch culture without pH control had a maximum concentration of EPS and endopolysaccharides, which was much lower than those with pH control. Maximum mycelial growth (12.5 g/L) and EPS production (4.7 g/L) were achieved by shifting the controlled pH from 3.0 to 6.0 after day 4. The contrast between the controlled-pH process and uncontrolled pH was marked. By using various two-stage culture processes, it was also observed that culture pH has a significant affect on the yield of product, mycelial morphology, chemical composition, and molecular weight of EPS. A detailed observation of mycelial morphology revealed that the productive morphological form for EPS production was a dispersed pellet (controlled pH shifting from 3.0 to 6.0) rather than a compact pellet with a dense core area (controlled pH 4.5) or a feather-like pellet (controlled pH shifting from 6.0 to 3.0). Three different polysaccharides were obtained from each pH conditions, and their molecular weights and chemical compositions were significantly different.</P>