A novel process-based model of microbial growth: self-inhibition in Saccharomyces cerevisiae aerobic fed-batch cultures

Mazzoleni, Stefano; Landi, C.; Cartenì, Fabrizio; Alteriis, Elisabetta de; Giannino, Francesco; Paciello, Lucia; Parascandola, Palma

doi:10.1186/s12934-015-0295-4

Cited by 40 publications

(52 citation statements)

References 82 publications

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“…Previous work on S. cerevisiae has suggested maximal yields depend on a balance between feeding enough sugar to maintain high product flux, but not too much as to induce overflow metabolism (Mazzoleni et al, 2015). To that end, we set up 2-L scale bioreactors with feed strategies aimed at minimizing overflow metabolism and maximizing titer.…”

Section: Fed-batch Bioreactor Fermentationsmentioning

confidence: 99%

Engineering high-level production of fatty alcohols by Saccharomyces cerevisiae from lignocellulosic feedstocks

d’Espaux

Ghosh

Runguphan

et al. 2017

Metabolic Engineering

104

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A B S T R A C TFatty alcohols in the C12-C18 range are used in personal care products, lubricants, and potentially biofuels. These compounds can be produced from the fatty acid pathway by a fatty acid reductase (FAR), yet yields from the preferred industrial host Saccharomyces cerevisiae remain under 2% of the theoretical maximum from glucose. Here we improved titer and yield of fatty alcohols using an approach involving quantitative analysis of protein levels and metabolic flux, engineering enzyme level and localization, pull-push-block engineering of carbon flux, and cofactor balancing. We compared four heterologous FARs, finding highest activity and endoplasmic reticulum localization from a Mus musculus FAR. After screening an additional twenty-one single-gene edits, we identified increasing FAR expression; deleting competing reactions encoded by DGA1, HFD1, and ADH6; overexpressing a mutant acetyl-CoA carboxylase; limiting NADPH and carbon usage by the glutamate dehydrogenase encoded by GDH1; and overexpressing the Δ9-desaturase encoded by OLE1 as successful strategies to improve titer. Our final strain produced 1.2 g/L fatty alcohols in shake flasks, and 6.0 g/L in fed-batch fermentation, corresponding to~20% of the maximum theoretical yield from glucose, the highest titers and yields reported to date in S. cerevisiae. We further demonstrate high-level production from lignocellulosic feedstocks derived from ionic-liquid treated switchgrass and sorghum, reaching 0.7 g/L in shake flasks. Altogether, our work represents progress towards efficient and renewable microbial production of fatty acidderived products.

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Section: Fed-batch Bioreactor Fermentationsmentioning

confidence: 99%

Engineering high-level production of fatty alcohols by Saccharomyces cerevisiae from lignocellulosic feedstocks

d’Espaux

Ghosh

Runguphan

et al. 2017

Metabolic Engineering

104

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“…The oil suspensions with 1% and 0.02% oil all showed an increase in total cells concentration, followed by a stationary phase (Figures and ). A stationary phase is generally caused by the lack of an essential nutrient or the accumulation of toxic compounds (Mazzoleni et al, ). The median total cell concentration of the measurements performed on the oil suspensions related to the initial oil amount of 1% was at least 10 8 cells/ml in the stationary phase.…”

Section: Discussionmentioning

confidence: 99%

Vegetable oils as carbon and energy source for Aureobasidium melanogenum in batch cultivation

et al. 2018

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Dark homogenous fungal‐based layers called biofinishes and vegetable oils are key ingredients of an innovative wood protecting system. The aim of this study was to determine which of the vegetable oils that have been used to generate biofinishes on wood will provide carbon and energy for the biofinish‐inhabiting fungus Aureobasidium melanogenum , and to determine the effect of the oil type and the amount of oil on the cell yield. Aureobasidium melanogenum was cultivated in shake flasks with different types and amounts of carbon‐based nutrients. Oil‐related total cell and colony‐forming unit growth were demonstrated in suspensions with initially 1% raw linseed, stand linseed, and olive oil. Oil‐related cell growth was also demonstrated with raw linseed oil, using an initial amount of 0.02% and an oil addition during cultivation. Nile red staining showed the accumulation of fatty acids inside cells grown in the presence of oil. In conclusion, each tested vegetable oil was used as carbon and energy source by A. melanogenum . The results indicated that stand linseed oil provides less carbon and energy than olive and raw linseed oil. This research is a fundamental step in unraveling the effects of vegetable oils on biofinish formation.

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“…In aerobic fermentation processes, the dissolved oxygen (DO) concentration is one of the most important operating parameters. The measurement and accurate control of the DO concentration is conducive to the calculation of the volumetric oxygen transfer coefficient (K L a), and it is also very important for the understanding of fermentation processes [5,6]. As oxygen deficiency will lead to either cessation of aerobic growth or a decrease in the efficiency of metabolism, as well as the production of undesirable by-products, maintaining a constant DO concentration in the growth medium is required for aerobic fermentation.…”

Section: Introductionmentioning

confidence: 99%

On-Line Tendency Control of Dissolved Oxygen Concentration during Aerobic Fed-Batch Fermentations

Zheng

Pan

2019

Applied Sciences

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In this paper, an on-line control strategy that aims to guarantee the maintenance of a minimum dissolved oxygen (DO) concentration during aerobic fed-batch fermentations is proposed. It is a difficult task to maintain the DO concentration, especially during fed-batch fermentation, due to strongly nonlinear, variable conditions and probe dynamics. The algorithm uses information contained in the slope of the profile of the DO, as this evolves in a timely way to adapt to process variations. Moving window technology was used to track the DO tendency variation. This method was tested in Corynebacterium glutamicum and Pichia pastoris fermentations. The performance of tendency control was compared with that of manual control. The experimental results clearly show that the on-line tendency control of DO is effective and can also reduce the frequency of activity of the controller as well as the manpower burden.

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A novel process-based model of microbial growth: self-inhibition in Saccharomyces cerevisiae aerobic fed-batch cultures

Cited by 40 publications

References 82 publications

Engineering high-level production of fatty alcohols by Saccharomyces cerevisiae from lignocellulosic feedstocks

Engineering high-level production of fatty alcohols by Saccharomyces cerevisiae from lignocellulosic feedstocks

Vegetable oils as carbon and energy source for Aureobasidium melanogenum in batch cultivation

On-Line Tendency Control of Dissolved Oxygen Concentration during Aerobic Fed-Batch Fermentations

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