Bubble coalescence behaviour in biological media

Adler, I.; Diekmann, J.; Hartke, W.; Hecht, V.; Rohn, F.; Sch�gerl, K.

doi:10.1007/bf00508605

Cited by 20 publications

(3 citation statements)

References 8 publications

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“…The results shown in Table 2 indicate that in the range of concentrations of insoluble substrates studied no signi®cant differences in the O 2 transfer rate are observed. Also Adler et al [29] showed that a small oil fraction of about 0.5±1.5% (v/v) present in the medium affected slightly the k L a value. …”

Section: Oxygen Transfer Coefficientmentioning

confidence: 99%

Production of extracellular lipase by Candida cylindracea CBS 6330

Sokolovska

Albasi²,

Riba³

et al. 1998

Bioprocess Engineering

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In this study we investigated the in¯uences of aeration, substrate type and concentration on extracellular lipase production in a batch fermentor. The use of air enriched with pure oxygen is the most suitable for the lipase production. Additionally, we found that the presence of fats in the culture broth did not affect the value of the volumetric mass transfer coef®cient of oxygen in our system. Olive oil or oleic acid was used as carbon sources. In both cases, the maximal speci®c rate of growth, l max , was the same but the highest activity was obtained when 10 g/dm 3 of olive oil were used as an initial substrate concentration.

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Section: Oxygen Transfer Coefficientmentioning

confidence: 99%

Production of extracellular lipase by Candida cylindracea CBS 6330

Sokolovska

Albasi²,

Riba³

et al. 1998

Bioprocess Engineering

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“…2 Unlimited foam formation and insuf®cient foam collapse can have serious effects in such aerated systems. These effects include: reduction in working volume, increased chances of contamination, suppression of oxygen transfer, 3 loss of active biomass, and fouling of sensors.…”

Section: Introductionmentioning

confidence: 98%

Performance characteristics of novel mechanical foam breakers in a stirred tank reactor

Deshpande

Barigou

1999

J. Chem. Technol. Biotechnol.

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Unlimited foam formation and insuf®cient foam collapse can have serious effects in an aerated system such as a fermentation process. Mechanical foam breakers are used in foam control to avoid the drawbacks associated with the use of chemical antifoams and defoaming agents. In this paper, two new foam breakers consisting of a two-blade paddle with three slits, and a two-blade paddle with 168 thin needles have been tested. They gave signi®cantly reduced critical speeds and power consumption for foam control in a stirred vessel, compared with some conventional foam breakers. The effects of various parameters, namely the physical properties of the foaming solution, type of gas sparger, surfactant concentration, and foam-breaker clearance above liquid level, have been investigated. The degree of dif®culty of controlling dynamic foams generated continuously in a stirred vessel is found to be a function of the nature of the foam, ie its bubble size, its liquid holdup, and the degree of foamability of the system.

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“…Because of their coalescence suppressing effect, the salts encourage the production of small bubbles, so enhancing the interfacial area u.11.23*24 Addition of casein peptone lowered the k,a; an effect also observed by Eckenfelder and BamhardtI4 and Adler et al with peptone or other proteins. Antifoam agents also reduce k,u, as shown by Adler et al , 11 Eckenfelder and Barnhardt14 and Voigt and Schugerl.lB Proteins and antifoam agents belong to the category (Voigt and Schugerl18) of polar organic compounds of high molecular weight and they are believed to suppress coalescence only after a long contact between bubbles and liquid, e.g. with the foam.…”

Section: Effect Of the Composition Of The Mediummentioning

confidence: 87%