ISSN:0006-3592    

DOI:10.1002/bit.260191102

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1977

数据来源: WILEY

摘要:

AbstractThe yeasts Saccharomyces cerevisiae, Candida utilis, and Candida lipolytica were used to investigate the action of different concentrations of fatty aeids (from acetic to myristic acid) on cell growth, division, uptake of inorganic phosphate, and substrate oxidation. The former two yeasts were found to undergo an inhibition of growth, cell division, and phosphate uptake at lower acid concentrations and to experience the inhibition of substrate oxidation at higher acid concentration. The concentration dependence of the action of fatty acids can be classified into four categories: (1) subthreshold concentrations which do not inhibit growth and have either no effect on, or stimulate, oxygen consumption; (2) threshold concentrations which lower the rate of growth, cell division, and phosphate uptake but do not inhibit the oxidation of carbon substrate; (3) above threshold concentrations which inhibit partially even substrate oxidation, and (4) microbicide concentrations.Candida lipolyticadisplays the Same sensitivity toward the action of fatty acids as the above yeast species; however, the threshold concentrations are higher and can be quickly lowered owing to oxidation by the yeast. The concentrations of fatty acids found in the medium after cultivations of yeast withn‐alkanes are of the same order as limiting concentrations; the formation of acids with twelve and less carbons in the molecule can thus be assumed to be one of the basic reasons for the lowering of biomass yields during cultivations on these hydrocarbon

ISSN:0006-3592    

DOI:10.1002/bit.260191103

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1977

数据来源: WILEY

摘要:

AbstractThe application of the enzyme thermistor in the analysis of cyanide in standard solutions as well as in blast furnace waste water is described. The heat signal is generated in the conversion of cyanide, catalyzed by the immobilized enzymes rhodanese (E.C. 2.8.1.1) and injectase (E.C. 4.4.19). Using the combination of cyanide‐metabolizing enzymes and the enzyme thermistor unit, assays down to 20μMcyanide can be carried out. Linear relationships were obtained at 20–600μMcyanide for injectase and 20–1000μMfor rhodanese. The stability at 27°C of the heat response was initially decreased, but soon stabilized at about 80% of the initial value and remained so for at least 200 hr. The technique was easily adapted to continuous analysis, applicable to environmental control (e.g., a “cyanide guard”) with a response time at present within 2–3 min after a sudden change in cyanide concentrati

ISSN:0006-3592    

DOI:10.1002/bit.260191104

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1977

数据来源: WILEY

摘要:

AbstractA continuous stirred tank fermentor (CSTF) used for cultivation of the fungusMorchella crassipesin ammonia base waste sulfite liquor (NH3‐WSL) was considered as a multivariable linear system around its operating point. Pulse testing on the inputs (inlet jacket temperature, inlet pH, inlet substrate concentration) and their responses at the outputs (biomass, outlet temperature, outlet jacket temperature, outlet pH, outlet substrate concentration) were used for numerical determination of the transfer function matri

ISSN:0006-3592    

DOI:10.1002/bit.260191105

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1977

数据来源: WILEY

摘要:

AbstractThe stereospecific hydrolysis ofD,L‐phenylalanine methylester with immobilized α‐chymotrypsin was carried out as a model reaction for the racemate resolution of aromatic amino acids in a five staged fluidized‐bed reactor (FBR). Owing to ester hydrolysis, a pH shift occurred along the reactor. Because of the pH‐dependent enzyme activity a particular longitudinal pH profile had to be enforced by a proper entrance pH in order to gain an optimum conversion. In the FBR with optimum pH profile, higher conversions were achieved than in a continuous stirred tank reactor (CSTR) at the pH optimum and at the same contact time. By the application of a proton balance and the results of kinetic measurements a model was developed for the prediction of the optimum longitudinal pH profile with regard to the maximum co

ISSN:0006-3592    

DOI:10.1002/bit.260191106

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1977

数据来源: WILEY

摘要:

AbstractA simple, low‐priced 30 liter tower‐type algal pilot plant for the cultivation of light‐ and motion‐sensitive species is described. Two hundred g wet weight ofMicrocystis aeruginosawere obtained per harvest. Since the self‐shading of denser cultures could be compensated for only to a limited extent by increasing the light intensity without damaging the cells, the efficiency of various culture‐vessel widths was determined for the growth ofMicrocystis: the best results were obtained with a width of 3.5 cm. Light requirements ofMicrocystiswere studied in shadowless suspensions. The compensation point of photosynthesis varied between 200 and 300 lx, depending on the preillumination, whereas the light saturation point was found to be near 4000 Ix. The light optimum for photosynthesis was not identical with that for

ISSN:0006-3592    

DOI:10.1002/bit.260191107

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1977

数据来源: WILEY

摘要:

AbstractAlcohol yields of 6.5% were obtained withSaccharomyces cerevisiaein lactasehydrolyzed acid whey permeate containing 30–35% total solids. Maximum alcohol yields obtained withKluyveromyces fragiliswere 4.5% in lactase‐hydrolyzed acid whey permeate at a solids concentration of 20% and 3.7% in normal permeate at a solids concentration of 10%.Saccharomyces cerevisiaeefficiently converted the glucose present in lactase‐hydrolyzed whey permeates containing 5–30% total solids (2–13% glucose) to alcohol. However, the galactose, which comprised about half the available carbohydrate in lactase‐hydrolyzed whey, was not utilized byS. cerevisiae, so that even though alcohol yields were higher when this organism was used, the process was wasteful in that a substantial proportion of the substrate was not fermented. For the process to become commercially feasible, an efficient means of rapidly converting both the galactose and glucose to alcohol mu

ISSN:0006-3592    

DOI:10.1002/bit.260191108

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1977

数据来源: WILEY

摘要:

AbstractPapain and lipase were immobilized on derivatized Sepharose 4‐B. The activated agarose had a binding capacity of 1.2 μmol amino groups/ml packed agarose or 17 mg proteins/g dry agarose. The immobilized enzyme preparations were tested for the effects of pH of assay, temperature of assay, and substrate concentrations. The effect of6Murea on the activity of papain was also determined. Soluble forms of the enzymes were used for comparison. Immobilization of the enzymes resulted in slightly different pH and temperature optima for activities. For immobilized papainKm(app) was similar to the one observed with soluble papain. Immobilization of lipase, however, caused a decrease inKmvalues. The immobilized enzyme preparations were stable when stored at 4°C and pH 7.5 for periods up to eight months. The soluble enzymes lost their activity within 96 hr under similar storage conditions. Immobilized papain did not lose any activity after treatment with6Murea for 270 min, whereas soluble papain lost 81% of its activity after the urea treatment, indicating that the immobilization of papain imparted structural and conformational stability to this enz

ISSN:0006-3592    

DOI:10.1002/bit.260191109

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1977

数据来源: WILEY

ISSN:0006-3592    

DOI:10.1002/bit.260191110

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1977

数据来源: WILEY

ISSN:0006-3592    

DOI:10.1002/bit.260191111

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1977

数据来源: WILEY