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M Kaieda

Publications and source records attributed to M Kaieda.

17 recordsLinked to original sources
PubMed2004

Enantioselective transesterification using immobilized Aspergillus oryzae overexpressing lipase.

In the present study, we used gene manipulation to construct a recombinant Aspergillus oryzae strain overexpressing lipase and investigated its application to the optical resolution of chiral compounds. A. oryzae niaD300, which was derived from the wild-type strain RIB40, was used as the host strain. The tglA gene, which encodes a triacylglycerol lipase, was cloned from the A. oryzae niaD300 chromosomal genome, then reintroduced, with and without a secretion-signal sequence, into the genome and expressed under the control of the improved glaA promoter of plasmid pNGA142. The resulting recombinant strain overexpressing A. oryzae lipase was immobilized within biomass-support particles and used as a whole-cell biocatalyst. The immobilized lipase-overexpressing strain with secretion-signal sequence showed high activity and was used to selectively synthesize (R)-1-phenylethyl acetate from (RS)-1-phenylethanol and vinyl acetate. After 48 h reaction at 30 degrees C with molecular sieve 4A, the yield and enantiomeric excess (%ee) of (R)-1-phenylethyl acetate reached approximately 90 and 95%ee, respectively. The whole-cell biocatalyst for optical resolution of chiral compounds produced in this study maintained its activity over 25 batch-reaction cycles.

Aspergillus oryzae↗
PubMed2001

Yeast whole-cell biocatalyst constructed by intracellular overproduction of Rhizopus oryzae lipase is applicable to biodiesel fuel production.

Yeast whole-cell biocatalysts for lipase-catalyzed reactions were constructed by intracellularly overproducing Rhizopus oryzae lipase (ROL) in Saccharomvces cerevisiae MT8-1. The gene encoding lipase from R. orvzae IFO4697 was cloned, and intracellular overproduction systems of a recombinant ROL with a pro-sequence (rProROL) were constructed. When rProROL from R. oryzae IFO4697 was produced under the control of the 5'-upstream region of the isocitrate lyase gene of Candida tropicalis (UPR-ICL) at 30 degrees C for 98 h by two-stage cultivation using SDC medium (SD medium with 2% casamino acids) containing 2.0% and 0.5% glucose, intracellular lipase activity reached levels up to 474.5 IU/l. These whole-cell biocatalysts were permeabilized by air-drying and used for the synthesis of methyl esters (MEs), a potential biodiesel fuel, from plant oil and methanol in a solvent-free and water-containing system. The ME content in the reaction mixture was 71 wt% after a 165-h reaction at 37 degrres C with stepwise addition of methanol. These results indicate that an efficient whole-cell biocatalyst can be prepared by intracellular overproduction of lipase in yeast cells and their permeabilization.

Amino Acid Sequence↗
PubMed2001

Whole cell biocatalyst for biodiesel fuel production utilizing Rhizopus oryzae cells immobilized within biomass support particles.

As part of a research program aimed at producing biodiesel fuel from plant oils enzymatically cells of Rhizopus oryzae (R. oryzae) IFO4697 (with a 1,3-positional specificity lipase) immobilized within biomass support particles (BSPs) were investigated for the methanolysis of soybean oil. The R. oryzae cells easily became immobilized within the BSPs during batch operation. To enhance the methanolysis activity of the immobilized cells under the culture conditions used, various substrate-related compounds were added to the culture medium. Among the compounds tested, olive oil or oleic acid was significantly effective. In contrast, no glucose was necessary. Immobilized cells were treated with several organic solvents, but none gave higher activity than untreated cells. When methanolysis was carried out with stepwise additions of methanol using BSP-immobilized cells, in the presence of 15% water the methyl esters (MEs) content in the reaction mixture reached 90% - the same level as that using the extracellular lipase. The process presented here, using a whole cell biocatalyst, is considered to be promising for biodiesel fuel production in industrial applications.

Journal Article↗
PubMed2001

Effect of methanol and water contents on production of biodiesel fuel from plant oil catalyzed by various lipases in a solvent-free system.

Methyl esters synthesized from plant oil and methanol by the methanolysis reaction are potentially important as a biodiesel fuel. The methanolysis of soybean oil by lipases from various microorganisms was investigated. Several of the lipases were found to catalyze methanolysis in a water-containing system without an organic solvent. The lipases from Candida rugosa, Pseudomonas cepacia, and Pseudomonas fluorescens displayed particularly high catalytic ability. The reaction rates of methanolysis catalyzed by the C. rugosa and P. fluorescens lipases decreased significantly when the water content was low, showing that water prevents the inactivation of these lipases by methanol. On the other hand, the methanolysis reaction rate catalyzed by the P. cepacia lipase remained high even under a low water content. In addition, the P. cepacia lipase gave high methyl ester contents in the reaction mixture up to 2 or 3 molar equivalents of methanol to oil, which is attributed to the P. cepacia lipase having substantial methanol resistance. For the same methanol content, the reaction rates of methanolysis catalyzed by the P. cepacia lipase increased with decreasing water content, and hence lipases strongly resistant to high methanol, such as that from P. cepacia, are desirable for use in methanolysis reaction processes.

Journal Article↗
PubMed2000

Pretreatment of immobilized Candida antarctica lipase for biodiesel fuel production from plant oil.

The effects of the pretreatment of immobilized Candida antarctica lipase enzyme (Novozym 435) on methanolysis for biodiesel fuel production were investigated. Methanolysis progressed much faster when Novozym 435 was preincubated in methyl oleate for 0.5 h and subsequently in soybean oil for 12 h. The initial reaction rate of methanolysis catalyzed by both the non-treated and preincubated enzyme decreased significantly with increasing water content. The initial reaction rate increased with increasing methanol content, showed a maximum, and thereafter decreased when the methanol content was increased further. The variation of the initial reaction rate with the methanol content was therefore analyzed using a Michaelis-Menten-type equation with substrate inhibition. Based on this equation, a procedure for the stepwise addition of methanol to the reaction mixture so as to maintain the desired methanol content was determined. When preincubated Novozym 435 was used, the ME content reached over 97% within 3.5 h by stepwise addition of 0.33 molar equivalent of methanol at 0.25-0.4 h intervals.

Journal Article↗
PubMed1999

Biodiesel fuel production from plant oil catalyzed by Rhizopus oryzae lipase in a water-containing system without an organic solvent.

A new enzymatic method of synthesizing methyl esters from plant oil and methanol in a solvent-free reaction system was developed. It is anticipated that such plant oil methyl esters can be used as a biodiesel fuel in the future. Lipase from Rhizopus oryzae efficiently catalyzed the methanolysis of soybean oil in the presence of 4-30 wt% water in the starting materials; however the lipase was nearly inactive in the absence of water. The methyl ester (ME) content in the reaction mixture reached 80-90 wt% by stepwise additions of methanol to the reaction mixture. The kinetics of the reaction appears to be in accordance with the successive reaction mechanism. That is, the oil is first hydrolyzed to free fatty acids and partial glycerides, and the fatty acids produced are then esterified with methanol. Although R. oryzae lipase is considered to exhibit 1(3)-regiospecificity, a certain amount of 1,3-diglyceride was obtained during the methanolysis and hydrolysis of soybean oil by R. oryzae lipase solution. Therefore, the high ME content in the reaction mixture is probably attributable to the acyl migration from the sn-2 position to the sn-1 or sn-3 position in partial glycerides.

Journal Article↗
PubMed1998

Pedicle transposition of the greater omentum for sternal osteomyelitis and mediastinitis after cardiac operation.

Three patients underwent pedicle transposition of the greater omentum for sternal osteomyelitis and mediastinitis after cardiac operation. These patients were previously operated on with coronary artery bypass grafting, aortic valve replacement and redo Fontan operation in each. This procedure was carried out on 4, 6, 8, and 14th postoperative day. The complications cured within about one month after the procedure in all cases. It is suggested that this maneuver is effective for obtaining healing osteomyelitis and mediastinitis following cardiac operation.

Adult↗
PubMed1996

[Use of the omentum for infected sternal dehiscence after aortic valve replacement--a case report].

A 68-year-old man had prosthetic valve replacement for aortic stenosis. Unfortunately, sternal dehiscence with osteomyelitis occurred on the fifth postoperative day. Implantation of the pedicled omentum to the wound was carried out three days later. The result was excellent. This is the worthy method to try to such wound of infected sternum with dehiscence. From the point of view of anatomy and physiology, the omentum has a great benefit to repair the infected space and promote the wound healing process.

Aged↗
PubMed1996

[Re-do Fontan operation--a case report].

A 32-year-old woman developed heart failure. She had received Glenn operation 26 years ago and Fontan operation using valved conduit (Björk-Shiley: 21 mm) seven years ago for tricuspid atresia type 1b. She underwent extirpation of the struck prosthetic valve. Neither graft stenosis nor pressure gradient between the right atrium and the pulmonary artery were observed on postoperative right arteriography. Sternotomy on redo Fontan operation should be carefully performed for preventing breaking down the implanted valved conduit. Though the prosthetic valve was not necessary on redo Fontan operation, anticoagulation after operation should be done.

Adult↗
PubMed1996

[Perforation and localized dissection of the left common iliac artery during the modified Bentall procedure: a case report].

We performed the modified Bentall procedure for annuloaortic ectasia in a 41-year-old man with Marfan's syndrome. Approximately 15 minutes after initiation of cardiopulmonary bypass with an arterial delivery via the left common femoral artery, perfusion volume gradually decreased and the abdomen of the patient was distended. Retrograde dissection was strongly suggested. Perforation and localized dissection of the left common iliac artery were recognized. Following repair of the lesion, the modified Bentall operation was carried out. Postoperative course was uneventful. The patient has been well for 22 months after the operation.

Adult↗
PubMed1995

[Difference in MRI findings and risk factors between multiple infarction without dementia and multi-infarct dementia].

MRI findings and risk factors for vascular dementia were evaluated with multi-variate analysis in 96 multi-infarct patients without dementia and 40 multi-infarct patients with dementia (MID). Only subjects with small infarcts in the territory of the perforator artery or deep white matter were studied. The diagnosis of MID was diagnosed according to DMS-III criteria and Hachinski's ischemia score. Location and area of patchy high-intensity areas including small infarcts, the degree of periventricular high intensity (PVH), and the degree of brain atrophy were examined with MR images. Independent variables were: history of hypertension, diabetes mellitus, other complications; systolic and diastolic blood pressure, atherosclerotic index, hematocrit, history of smoking, level of education, and activities of daily life (ADL). Hayashi's quantification method II was used to analyze the data. The most significant correlation was found between history of hypertension and dementia (partial correlation coefficient: 0.39). Significant correlations were also found between ADL and dementia (0.32), between thalamic infarction and dementia (0.31), and between PVH and dementia (0.27). Age, brain atrophy index, and history of diabetes mellitus contributed little to dementia. The contribution to dementia did not differ significantly between right and left patchy high-intensity areas on MR images. Location of infarcts, except for bilateral thalamic infarcts and large PVH, contributed little to dementia. Thus it would be difficult to base a prediction of the prevalence of vascular dementia on MRI findings. However, both hypertension and ADL contribute to vascular dementia and both are treatable, which may be significant for the prevention of dementia.

Aged↗
PubMed1991

[Clinical significance of periventricular high intensity lesions on magnetic resonance imaging in dementia].

In this study, vascular dementia (VD, 31 cases), senile dementia of Alzheimer type (DAT, 36 cases) and mixed type dementia (14 cases) were studied by means of magnetic resonance imaging (MRI). Diagnosis of dementia was made according to DSM-III and Hachinski's ischemic score. The areas of periventricular high intensity lesions (PVH) and those of brain parenchyma were measured by digitizer which was connected to a computer. The PVH score was obtained by dividing the areas of PVH by those of brain parenchyma at the level of the body of the lateral ventricule. A multiple variable analysis was applied to the PVH scores and risk factors for dementia using Hayashi's quantification method I. The multiple correlation coefficient between the PVH and the risk factors was 0.685. The most significant correlation was found between Hachinski's ischemic score and the PVH score (partial correlation coefficient: 0.58). Significant correlations were also found between ADL and the PVH score (0.25), as well as between the Hasegawa dementia score and the PVH score (0.24). Using the student T test, it was shown that the large PVH group was significantly correlated to poor ADL, whereas the small PVH group was not. The large PVH group in VD showed lower Hasegawa score than the small PVH group. On the other hand, there was no such correlation in DAT. PVH with prolongation of T2 could exist in various pathological states irrespective of their causes. Diffuse PVH tended to be frequently observed in VD together with poor ADL. It was therefore thought that brain ischemia was the main cause of PVH.

Aged↗
PubMedDate not supplied

Thoracoabdominal aortic aneurysms repair under abdominal cavity cooling with visceral shunting technique--a case report.

Mild hypothermia induced by abdominal cavity cooling together with a selective visceral shunting technique can be a useful adjunct for thoracoabdominal aortic aneurysm repair. The authors adopted this combined technique for repair of selected Crawford type III and type IV aneurysms to reduce visceral ischemic damage and minimize the incidence of postoperative complications.

Aortic Aneurysm, Abdominal↗