On-line monitoring of marine cyanobacterial cultivation based on phycocyanin fluorescence.

A novel on-line fluorescence monitoring system for marine cyanobacterial cultivation was developed. This method is based on the measurement of intracellular phycocyanin content, which is the major light harvesting protein. A fluorescence spectrophotometer, equipped with a flow cell connected with a culture liquid recycling tube was used.

Development of acetylcholine sensor using carbon fiber (amperometric determination).

An enzyme sensor is developed using carbon fiber to measure acetylcholine concentration. The mechanism is based on the detection of H2O2 which is a product of the sequential enzyme reactions of acetylcholinesterase and choline oxidase. The fabrication of the electrode is described.

Facile isolation of endo-pectate lyase from Erwinia carotovora based on electrostatic interaction.

Endo-pectate lyase (PATE) from Erwinia carotovora was selectively cosedimented with extracellularly produced lipopolysaccharide-lipid complex (LPSLC) through dialysis of the cell free culture broth. The selective isolation of PATE was confirmed by sodium dodecyl sulfate polyacrylamide gel electrophoresis. The cosedimentation of the PATE with LPSLC was initiated by decreasing conductivity of the solution and terminated at approx 1 m siemens (mScm-1).

On-line monitoring of the viscosity in dextran fermentation using piezoelectric quartz crystal.

A novel viscous sensor utilizing AT-cut quartz crystal to monitor the viscosity of fermentation broth was developed. The sensor system was constructed from the piezoelectric quartz crystal fixed to the cell, exposing only one side of the quartz crystal electrode, an oscillating circuit, a peak level meter, and a personal computer. In order to investigate the characteristics of the sensor system, a sensor signal relating to the resonant resistance of the quartz crystal was measured using dextran solutions with different molecular weights.

Air-bubbling, hollow-fiber reactor with cell bleeding and cross-flow filtration.

Continuous asymmetric reduction of dyhydrooxoisophorone (DOIP) to 4-hydroxy-2,2,6-trimethylcyclo-hexanone (4-HTMCH) was achieved by a thermophilic bacterium Bacillus stearothermophilus NK86-0151. Three reactors were used: an air-bubbling hollow-fiber reactor with cell bleeding and cross-flow filtration, an air-lift reactor, and a CSTR with PAA immobilized cells. The maximum cell concentration of 11.

Identification of proteins encoded in Escherichia coli hydA, hydB and analysis of the hydA locus.

The hydB gene of Escherichia coli, which is related with the expression of hydrogenase activity, was cloned into the plasmid (pES1). Using the maxicell protein-labeling method, the molecular weight of hydB gene product was estimated. Comparing between the gene products from the mutant strains and that of the hydB genes cloned strains, the molecular weight of the gene product was 35,000 Mr.

Microbial sensor for preliminary screening of mutagens utilizing a phage induction test.

For the preliminary screening of mutagens, a novel microbial sensor system was developed utilizing a phage induction test. Escherichia coli lysogenic strain GY5027 and nonlysogenic strain GY5026 were used in this study. The number of living cells was determined by measuring the respiration of cells immobilized onto an oxygen electrode.

Microbial conversion of beta-ionone by immobilized Aspergillus niger in the presence of an organic solvent.

Aspergillus niger JTS191 was capable of the conversion of beta-ionone to a mixture of its derivatives that is utilized to an essential oil of tobacco. The authors attempted this microbial conversion in the presence of an organic solvent to improve its reaction rate. The addition of isooctane accelerated the microbial conversion of beta-ionone.

Basic studies of hydrogen evolution by Escherichia coli containing a cloned Citrobacter freundii hydrogenase gene.

Citrobacter freundii genes that complemented Escherichia coli hyd-(hydrogenase activity) mutation were cloned in plasmids pCBH4 (6.2 kb) and pCBH6(5.7 kb).