研究者詳細 - 今村　維克

Fouling and cleaning of stainless steel surface: Adsorption and desorption behavior of bovine serum albumin and gelatin

T Sakiyama, T Toyomasu, A Nagata, K Imamura, K Nakanishi, T Takahashi, T Nagai

JOURNAL OF CHEMICAL ENGINEERING OF JAPAN 31 ( 2 ) 208 - 213 1998年4月

記述言語：英語出版者・発行元：SOC CHEMICAL ENG JAPAN

Adsorption and desorption behavior of bovine serum albumin (BSA) and gelatin on the surface of stainless steel particles are studied. The amount of BSA adsorbed increases significantly with temperature above 60 degrees C whereas that of gelatin decreases slightly with increasing temperature, Results of adsorption experiments with S-carboxymethylated BSA show that the thermal aggregation of BSA molecules at the surface through intermolecular thiol-disulfide interchange reactions plays an important role in the adsorption of BSA at elevated temperatures. Furthermore, the initial desorption rate constants and residual amounts of the two proteins during caustic and enzymatic cleanings of the fouled particles are compared under various conditions. As a result, a large difference is found in the temperature dependence of the initial desorption rate constant in caustic cleaning, suggesting different modes of adsorption of the proteins.

DOI： 10.1252/jcej.31.208

糖類アモルファス構造の相転移に及ぼすタンパク質の影響

Journal of Chemical Engineering of Japan 31 ( 3 ) 325 - 329 1998年

Performance of protease as a cleaning agent for stainless steel surfaces fouled with protein

T Sakiyama, T Toyomasu, A Nagata, K Imamura, T Takahashi, T Nagai, K Nakanishi

JOURNAL OF FERMENTATION AND BIOENGINEERING 85 ( 3 ) 297 - 301 1998年

記述言語：英語出版者・発行元：SOC FERMENTATION BIOENGINEERING, JAPAN

Cleaning experiments were performed by feeding protease solutions as cleaning agents into a packed column of stainless steel particles fouled with beta-lactoglobulin or gelatin. By evaluating the initial desorption rate constants (Brst-order rate constants) and residual amounts of protein, the cleaning efficiencies of the proteases were compared. The initial desorption rate constant depended on the kind of protease used and also on the type of protein to be removed. It increased with protease concentration and reached a constant value at a limit concentration. Kinetic analysis of the proteolytic reactions catalyzed by the proteases revealed that protease with a large Vm(ax)/EKm value for the proteolytic reaction resulted in a large value of the initial desorption rate constant in the enzymatic cleaning at a low protease concentration. The K-m value affected the limit concentration of protease yielding a saturation of initial desorption rate constant.

DOI： 10.1016/S0922-338X(97)85678-4

Development of a cylindrical apparatus for membrane-surface liquid culture and production of kojic acid using Aspergillus oryzae NRRL484

Y Wakisaka, T Segawa, K Imamura, T Sakiyama, K Nakanishi

JOURNAL OF FERMENTATION AND BIOENGINEERING 85 ( 5 ) 488 - 494 1998年

記述言語：英語出版者・発行元：SOC FERMENTATION BIOENGINEERING, JAPAN

To apply membrane-surface liquid culture (MSLC), reported in previous papers (J. Ferment. Bioeng., 80: 35-40, 41-46, 1995) to large-scale production, a novel bioreactor was constructed in which molds were grown on the outer surface of a cylindrical porous membrane facing the air with liquid medium running down along its inner surface. We cultivated Aspergillus oryzae NRRL484 to produce kojic acid as a model secondary metabolite. An SE20 membrane composed of polysulfone with a nominal pore diameter of 0.2 mu m (Fuji Photo Film Co.) was found to be most suitable based on the facts that the mass transfer through the membrane had no appreciable effect on the kojic acid production and the mycelia did not pass through the membrane pores. Kojic acid was produced at higher levels than in shaking flask culture. The highest kojic acid concentration in the batch MSLCs using the cylindrical membrane module with an active surface area of 220 cm(2) was 14, 45, and 60 mg/ml for glucose concentrations in the medium of 5, 10, and 20%, respectively. In the shaking flask cultures using 10 and 20% glucose, the maximum kojic acid concentrations were 24 and 22 mg/ml, respectively. In the MS;LC, the liquid medium was quite clear without any contamination of cells. Furthermore, the mold was highly stable against autolysis, and continuous cultivation with holding tells on the membrane surface could be conducted for over 70 d. When the average feed rate of the medium containing 10% glucose and 0.1% yeast extract was 30 ml/d, the steady-state kojic acid concentration at the outlet of the MSLC apparatus was in the range of 45-50 mg/ml.

DOI： 10.1016/S0922-338X(98)80067-6