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Yoo, Sun Kyun,Kim, Do Man,Donal F. Day 한국미생물 · 생명공학회 2001 Journal of microbiology and biotechnology Vol.11 No.4
The influence of process conditions on highly branched glucooligosaccharides production by mixed culture of Leuconostoc mesenteroides ATCC 13146 and Lipomyces starkeyi ATCC 74054 was studied. We divided the batch culture fermentations into two groups according to inoculation method. One-point inoculation was performed by coinoculation of L. mesenteroides and L. starkeyi at the ratio of 10 to 1, and two-point inoculation by L. mesenteroides inoculation first and L. starkeyi inoculation after L. mesenteroides grew to the end of the log phase of growth. Two-point inoculation improved the yield of oligosaccharide by 1.5 to 2.0 fold more than one-point inoculation. In this process, the highest yield of oligosaccharides (48% of theoretical yield) and productivity (0.85 g/l/h) were obtained with starch as an initial substrate for L. starkeyi growth. The estimated composition of the end product consisted of 31.5% oligosaccharides, 17.6% dextran, and 46.5% mannitol.
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>
Enhanced Saccharification of Rice Straw Using Hypochloritehydrogen Peroxide
강희경,Nahyun M. Kim,Ghahyun J. Kim,Eun-Seong Seo,Hwa-Ja Ryu,Sang-Il Yun,Hyun-Chul Choi,Donal F. Day,Jongho Kim,Dong-Lyun Cho,김도만 한국생물공학회 2011 Biotechnology and Bioprocess Engineering Vol.16 No.2
Rice straw is a lignocellulosic biomass, and has been recognized as a renewable organic substance and alternative energy source. In this study, rice straw was pretreated with hypochlorite-hydrogen peroxide (Ox-B)solution. The optimal pretreatment conditions were determined via response surface methodology, and the pretreated rice straw was hydrolyzed with exo-glucanase, endoglucanase,hemicellulase, and β-glucosidase Accellerase 1000™ (endo-glucanase equivalent activity of 1,250 carboxy methyl cellulose (CMC) U/g of rice straw pretreated for 24h). The optimal conditions were as follows: 60 min pretreatment using Ox-B solution containing 0.6% hypochlorite and 25% hydrogen peroxide for 1 g of rice straw in a total reaction volume of 240 mL. Under these conditions, 406.8mg of D-glucose and 224.0 mg of D-xylose were obtained from 1 g of rice straw. The fermentation of enzymatic hydrolysates containing 8.14 g/L D-glucose and 4.49 g/L D-xylose with Pichia stipitis generated 3.65 g/L of ethanol with a corresponding yield of 0.37 g/g. The maximum possible ethanol conversion rate is 72.54%.
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>
Glucanhydrolase from Lipomyces starkeyi KSM 22 as Potential Mouthwash Ingredient
KIM, DOMAN,RYU, SU-JIN,SON, EUN-JU,CHUNG, HYUN-JU,KIM, SEUNG-HEUK,KIM, DO-WON,DAY, DONAL F. 한국미생물 · 생명공학회 2002 Journal of microbiology and biotechnology Vol.12 No.6
A glucanhydrolase (a DXAMase exhibiting both dextranolytic and amylolytic activities) from Lipomyces starkeyi KSM 22 hydrolyzed polysaccharides having α-(1→3)-, α-(1→4)-, and α-(1→6)-D-glucosidic likages. The oral hygiene benefits of DXAMase-containing mouthwash were examined in relation to human experimental gingivitis during a 3-week period without brushing. The DXAMase-treated group exhibitied a lower increase in plaque accumulation and gingival index score than the chlorhexidine-treated group. The DXAMase-treated group also showed less tongue accumulation, had taste, and tooth staining, thus indicating a positive role for DXAMase as an antiplaque agent ingredient.
Moon, Young Hwan,Madsen, Lee,Chung, Chang-Ho,Kim, Doman,Day, Donal F Published by Stockton Press on behalf of the Socie 2015 Journal of industrial microbiology & biotechnology Vol.42 No.2
<P>We have previously demonstrated the production of glucooligosaccharides via a fermentation of sucrose with Leuconostoc mesenteroides NRRL B-742 using sodium hydroxide (NaOH) to control the pH. Because NaOH is expensive, we sought to minimize the cost of our process by substituting hydrated lime and saccharate of lime (lime sucrate) in its place. The yield of glucooligosaccharides using either 5 % lime (41.4 ± 0.5 g/100 g) or 5 % lime sucrate (40.0 ± 1.4 g/100 g) were both similar to the NaOH control (42.4 ± 1.5 g/100 g). Based on this, it appears that the cost associated with pH control in our process can be reduced by a factor of approximately 2.4 using lime instead of NaOH. Because our chromatographic stage is based on a Ca(2+)-form resin to separate glucooligosaccharides, the use of lime not only negates the need for costly de-salting via ion-exchange (elimination of two ion-exchange sections) prior to separation, but also greatly reduces the resin regeneration cost.</P>