Factors affecting the estimation of intracellular ethanol concentrations

Dasari, G.; Roddick, Felicity; Connor, M.; Pamment, Neville B.

doi:10.1007/bf01386368

Cited by 41 publications

(31 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A difference between the inhibitory effect of added and produced ethanol, in conjunction with different intracellular and extracellular ethanol concentrations, was proposed for yeast in studies prior to 1983 (34,479,497). However, subsequent unrebutted work has discounted this hypothesis for yeast (133,134,135,229,395), Z. mobilis (313), and E. coli (168). In light of these data and in particular biophysical analyses indicating that substantial differences between intracellular and extracellular ethanol concentrations across plasma membranes can exist for at most short periods (313,395), it would appear unlikely that this discrepancy is due to a difference in the inhibitory effect of added and produced ethanol.…”

Section: Native Cellulolytic Strategymentioning

confidence: 99%

Microbial Cellulose Utilization: Fundamentals and Biotechnology

Lynd

Weimer

Zyl³

et al. 2002

Microbiol Mol Biol Rev

4,005

2,868

View full text Add to dashboard Cite

Fundamental features of microbial cellulose utilization are examined at successively higher levels of aggregation encompassing the structure and composition of cellulosic biomass, taxonomic diversity, cellulase enzyme systems, molecular biology of cellulase enzymes, physiology of cellulolytic microorganisms, ecological aspects of cellulase-degrading communities, and rate-limiting factors in nature. The methodological basis for studying microbial cellulose utilization is considered relative to quantification of cells and enzymes in the presence of solid substrates as well as apparatus and analysis for cellulose-grown continuous cultures. Quantitative description of cellulose hydrolysis is addressed with respect to adsorption of cellulase enzymes, rates of enzymatic hydrolysis, bioenergetics of microbial cellulose utilization, kinetics of microbial cellulose utilization, and contrasting features compared to soluble substrate kinetics. A biological perspective on processing cellulosic biomass is presented, including features of pretreated substrates and alternative process configurations. Organism development is considered for “consolidated bioprocessing” (CBP), in which the production of cellulolytic enzymes, hydrolysis of biomass, and fermentation of resulting sugars to desired products occur in one step. Two organism development strategies for CBP are examined: (i) improve product yield and tolerance in microorganisms able to utilize cellulose, or (ii) express a heterologous system for cellulose hydrolysis and utilization in microorganisms that exhibit high product yield and tolerance. A concluding discussion identifies unresolved issues pertaining to microbial cellulose utilization, suggests approaches by which such issues might be resolved, and contrasts a microbially oriented cellulose hydrolysis paradigm to the more conventional enzymatically oriented paradigm in both fundamental and applied contexts

show abstract

Section: Native Cellulolytic Strategymentioning

confidence: 99%

Microbial Cellulose Utilization: Fundamentals and Biotechnology

Lynd

Weimer

Zyl³

et al. 2002

Microbiol Mol Biol Rev

4,005

2,868

View full text Add to dashboard Cite

show abstract

“…In addition, the biotransformation product, benzyl alcohol, has been shown to directly affect membrane fluidity in studies using erythrocyte^.^^ The actual values of intracellular substrates and products must be interpreted with caution because they are dependent on the accuracy of estimates of intracellular volume and are influenced by laboratory methodology. '2,24- 26 In addition, overall intracellular levels ignore internal distribution among cell wall, membrane, and cytoplasmic phases.…”

Section: Discussionmentioning

confidence: 99%

Biotransformation of benzaldehyde by Saccharomyces cerevisiae: Characterization of the fermentation and toxicity effects of substrates and products

Long

Ward

1989

Biotech & Bioengineering

View full text Add to dashboard Cite

Although higher initial rates of phenylacetyl carbinol formation were observed in fermentations containing a high starting benzaldehyde level, a massive reduction in yeast viability was observed resulting in early cessation of production formation. Pulse feeding to maintain lower benzaldehyde concentrations resulted in a lower initial reaction rate, but prolonged yeast viability and the biotransformation. This resulted in higher overall product tilers. As benzaldehyde concentration was increased, yeast growth rate was reduced (0.5 g/L), inhibited (1-2 g/L), or cell viability reduced (3 g/L). Benzaldehyde appeared to alter the cell permeability barrier to substrates and products. Reductions in yeast biomass levels and especially protein and lipid content were observed during the biotransformation. The effects of benzaldehyde and reaction products on yeast pyruvate decarboxylase and alcohol dehydrogenase stability were determined. Homogenized yeast cells produced similar phenylacetyl carbinol levels to whole yeast only if supplemented with thiamine pyrophosphate and magnesium.

show abstract

“…Analyses Cell numbers were determined using a Coulter Counter as previously described (Dasari et al, 1983). The maximum specific growth rate during the exponential phase pm was determined from a linear regression fit of the semilog plot of cell growth.…”

Section: Methodsmentioning

confidence: 99%