Agitation effects in yeast propagation

West, J. M.; Garden, Elmer L.

doi:10.1002/jbmte.390010204

Cited by 7 publications

(2 citation statements)

References 10 publications

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“…It is probably due to enhanced agitation in fluid due to cyclic rise-sink of the object which raises the area of contact and the relative velocity between cells and the fluid layer [29]. Note that an increase in yeast population through external mechanical mixing has been weakly reported by a few past studies [30,31].…”

Section: The Rise-sink Cyclementioning

confidence: 96%

Non-biodegradable objects may boost microbial growth in water bodies by harnessing bubbles

2021

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Given the ubiquity of bubbles and non-biodegradable wastes in aqueous environments, their transport through bubbles should be widely extant in water bodies. In this study, we investigate the effect of bubble-induced waste transport on microbial growth by using yeasts as model microbes and a silicone rubber object as model waste. Noteworthily, this object repeatedly rises and sinks in fluid through fluctuations in bubble-acquired buoyant forces produced by cyclic nucleation, growth and release of bubbles from object's surface. The rise–sink movement of the object gives rise to a strong bulk mixing and an enhanced resuspension of cells from the floor. Such spatially dynamic contaminant inside a nutrient-rich medium also leads to an increment in the total microbe concentration in the fluid. The enhanced concentration is caused by strong nutrient mixing generated by the object's movement which increases the nutrient supply to growing microbes and thereby, prolonging their growth phases. We confirm these findings through a theoretical model for cell concentration and nutrient distribution in fluid medium. The model is based on the continuum hypothesis and it uses the general conservation law which takes an advection–diffusion growth form. We conclude the study with the demonstration of bubble-induced digging of objects from model sand.

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Section: The Rise-sink Cyclementioning

confidence: 96%

Non-biodegradable objects may boost microbial growth in water bodies by harnessing bubbles

2021

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“…In most cases, the proposed inventions on air distribution in liquid fermentation media relied much on excellent mixing devices to break air bubbles and distribute them in the most efficient manner so air would remain as long as possible in the liquid column. Conditions that result in improved mixing of liquid media are likely to improve yeast yield, although increased agitation as such would have a minor effect (West and Gaden ). Many styles of air diffusers were invented.…”

Section: Aerationmentioning

confidence: 99%

Aeration and Foam Control in Baker's Yeast Production: Mapping Patents

Gélinas

2016

Comp Rev Food Sci Food Safe

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A key ingredient in the baking industry, baker's yeast must be produced under strict controlled conditions. High yields of baker's yeast cannot be attained unless a huge quantity of air is injected into fermentation vats. This review of 245 patent specifications shows that inventors have paid much attention to the distribution of fine air bubbles in order to optimize oxygen transfer to the yeast cells. Technical solutions to reduce energy costs associated with aeration are also proposed. Intense aeration caused foaming problems, so mechanical destruction of foam was first proposed until inventions on specific chemical antifoams were patented. In recent years, the development of cheaper and more efficient foam control techniques has remained an issue. Aeration during yeast growth in tanks impairs its fermentative activity in anaerobic bread dough. Since the beginning of the 20th century, massive adoption of air-grown fed-batch baker's yeast probably encouraged sugar addition to stimulate yeast gassing activity in pan bread characterized by high loaf volume, especially those prepared under short dough fermentation conditions.

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Automatic control of dissolved oxygen levels in fermentations

Siegell

Gaden

1962

Biotech & Bioengineering

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SummaryDissolved oxygen levels in fermentation systems are affected by ( a ) gas flow rate, ( b ) degree of agitation, and (c) oxygen partial pressure in the gas. Since the first two variables cannot easily be separated, a method for dissolved oxygen control has been devised based on the variation of oxygen partial pressure in the gas. Oxygen and nitrogen are fed to a special mixing valve capable of varying the proportions of the two gases while keeping the total flow rate constant. A dissolved oxygen electrode and control system adjust the valve setting to automatically maintain a preset oxygen level. Oxygen analyzers, monitoring the inlet and outlet gas streams, provide additional information from which oxygen absorption and uptake rates may be determined. The system provides a means for the quantitative and independent study of aeration and agitation effects. In addition, it offers a basis for routine control of oxygen levels in plant fermentation equipment.

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Agitation effects in yeast propagation

Cited by 7 publications

References 10 publications

Non-biodegradable objects may boost microbial growth in water bodies by harnessing bubbles

Non-biodegradable objects may boost microbial growth in water bodies by harnessing bubbles

Aeration and Foam Control in Baker's Yeast Production: Mapping Patents

Automatic control of dissolved oxygen levels in fermentations

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