Evolution of a recombinant (gucoamylase‐producing) strain of <i>Fusarium venenatum</i> A3/5 in chemostat culture

Wiebe, Marilyn G.; Robson, Geoffrey D.; Shuster, J. R.; Trinci, Anthony P. J.

doi:10.1002/bit.1046

Cited by 23 publications

(12 citation statements)

References 45 publications

(45 reference statements)

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“…Culture pH was kept constant at pH 7.0 by the addition of sterile 1 M KOH or 1 M H 3 PO 4 . Polypropylene glycol (1:1 mixture of M n ~1000 and M n ~2000, [25]) was added to control foam production.…”

Section: Methodsmentioning

confidence: 99%

Production of scopularide A in submerged culture with Scopulariopsis brevicaulis

et al. 2014

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BackgroundMarine organisms produce many novel compounds with useful biological activity, but are currently underexploited. Considerable research has been invested in the study of compounds from marine bacteria, and several groups have now recognised that marine fungi also produce an interesting range of compounds. During product discovery, these compounds are often produced only in non-agitated culture conditions, which are unfortunately not well suited for scaling up. A marine isolate of Scopulariopsis brevicaulis, strain LF580, produces the cyclodepsipeptide scopularide A, which has previously only been produced in non-agitated cultivation.ResultsScopulariopsis brevicaulis LF580 produced scopularide A when grown in batch and fed-batch submerged cultures. Scopularide A was extracted primarily from the biomass, with approximately 7% being extractable from the culture supernatant. By increasing the biomass density of the cultivations, we were able to increase the volumetric production of the cultures, but it was important to avoid nitrogen limitation. Specific production also increased with increasing biomass density, leading to improvements in volumetric production up to 29-fold, compared with previous, non-agitated cultivations. Cell densities up to 36 g L-1 were achieved in 1 to 10 L bioreactors. Production of scopularide A was optimised in complex medium, but was also possible in a completely defined medium.ConclusionsScopularide A production has been transferred from a non-agitated to a stirred tank bioreactor environment with an approximately 6-fold increase in specific and 29-fold increase in volumetric production. Production of scopularide A in stirred tank bioreactors demonstrates that marine fungal compounds can be suitable for scalable production, even with the native production organism.

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Section: Methodsmentioning

confidence: 99%

Production of scopularide A in submerged culture with Scopulariopsis brevicaulis

et al. 2014

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“…Culture pH was kept constant at pH 4.0 by the addition of sterile 1 M KOH or 1 M H 3 PO 4 . Clerol FBA 3107 antifoam (Cognis France, Ponthierry Paris; 0.01% v/v for batch cultures) or polypropylene glycol (mixed molecular weight [17], 0.1% v/v for fed-batch cultures) was added to control foam production. Gas concentration (CO 2 , O 2 , N 2 and Ar) was analysed continuously in an Omnistar quadrupole mass spectrometer (Balzers AG, Liechtenstein), calibrated with 3% CO 2 in Ar.…”

Section: Methodsmentioning

confidence: 99%

Lipid production in batch and fed-batch cultures of Rhodosporidium toruloidesfrom 5 and 6 carbon carbohydrates

et al. 2012

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BackgroundMicrobial lipids are a potential source of bio- or renewable diesel and the red yeast Rhodosporidium toruloides is interesting not only because it can accumulate over 50% of its dry biomass as lipid, but also because it utilises both five and six carbon carbohydrates, which are present in plant biomass hydrolysates.MethodsR. toruloides was grown in batch and fed-batch cultures in 0.5 L bioreactors at pH 4 in chemically defined, nitrogen restricted (C/N 40 to 100) media containing glucose, xylose, arabinose, or all three carbohydrates as carbon source. Lipid was extracted from the biomass using chloroform-methanol, measured gravimetrically and analysed by GC.ResultsLipid production was most efficient with glucose (up to 25 g lipid L−1, 48 to 75% lipid in the biomass, at up to 0.21 g lipid L−1 h−1) as the sole carbon source, but high lipid concentrations were also produced from xylose (36 to 45% lipid in biomass). Lipid production was low (15–19% lipid in biomass) with arabinose as sole carbon source and was lower than expected (30% lipid in biomass) when glucose, xylose and arabinose were provided simultaneously. The presence of arabinose and/or xylose in the medium increased the proportion of palmitic and linoleic acid and reduced the proportion of oleic acid in the fatty acids, compared to glucose-grown cells.High cell densities were obtained in both batch (37 g L−1, with 49% lipid in the biomass) and fed-batch (35 to 47 g L−1, with 50 to 75% lipid in the biomass) cultures. The highest proportion of lipid in the biomass was observed in cultures given nitrogen during the batch phase but none with the feed. However, carbohydrate consumption was incomplete when the feed did not contain nitrogen and the highest total lipid and best substrate consumption were observed in cultures which received a constant low nitrogen supply.ConclusionsLipid production in R. toruloides was lower from arabinose and mixed carbohydrates than from glucose or xylose. Although high biomass and lipid production were achieved in both batch and fed-batch cultures with glucose as carbon source, for lipid production from mixtures of carbohydrates fed-batch cultivation was preferable. Constant feeding was better than intermittent feeding. The feeding strategy did not affect the relative proportion of different fatty acids in the lipid, but the presence of C5 sugars did.

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“…The culture pH was kept constant at pH 4.5, 4.9, or 5.5 by the addition of sterile 1 M KOH or 1 M H 3 PO 4 . Polypropylene glycol (mixed molecular weight [21]) was added to control foam production. The initial biomass concentration in T. reesei cultures was 0.3 g liter Ϫ1 , and in A. niger cultures the concentrations were 0.4 g liter Ϫ1 in bioreactors and 0.7 to 1.4 g liter Ϫ1 in flasks.…”

Section: Methodsmentioning

confidence: 99%

Engineering Filamentous Fungi for Conversion of d -Galacturonic Acid to l -Galactonic Acid

Kuivanen

Mojžita

Wang

et al. 2012

Appl Environ Microbiol

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D-Galacturonic acid, the main monomer of pectin, is an attractive substrate for bioconversions, since pectin-rich biomass is abundantly available and pectin is easily hydrolyzed. L-Galactonic acid is an intermediate in the eukaryotic pathway for D-galacturonic acid catabolism, but extracellular accumulation of L-galactonic acid has not been reported. By deleting the gene encoding L-galactonic acid dehydratase (lgd1 or gaaB) in two filamentous fungi, strains were obtained that converted D-galacturonic acid to L-galactonic acid. Both Trichoderma reesei ⌬lgd1 and Aspergillus niger ⌬gaaB strains produced L-galactonate at yields of 0.6 to 0.9 g per g of substrate consumed. Although T. reesei ⌬lgd1 could produce L-galactonate at pH 5.5, a lower pH was necessary for A. niger ⌬gaaB. Provision of a cosubstrate improved the production rate and titer in both strains. Intracellular accumulation of L-galactonate (40 to 70 mg g biomass ؊1 ) suggested that export may be limiting. Deletion of the L-galactonate dehydratase from A. niger was found to delay induction of D-galacturonate reductase and overexpression of the reductase improved initial production rates. Deletion of the L-galactonate dehydratase from A. niger also delayed or prevented induction of the putative D-galacturonate transporter An14g04280. In addition, A. niger ⌬gaaB produced L-galactonate from polygalacturonate as efficiently as from the monomer. D-Galacturonic acid is the principal component of pectin, a major constituent of sugar beet pulp and citrus peel, which are abundant and inexpensive raw materials. The annual worldwide production of sugar beet and citrus fruit is about 250 ϫ 10 6 and 115 ϫ 10 6 metric tons, respectively. After beet processing, 5 to 10% of the sugar beet remains as dried sugar beet pulp. This pulp contains ca. 25% pectin (6). Citrus peel contains ca. 20% pectin on a dry mass basis. Sugar beet pulp and citrus peel are mainly used as cattle feed, or they are dumped. The use as cattle feed requires that the pulp and peel are dried since; otherwise, they rot rapidly. Disposal of the material is problematic because of the bad odor generated at the dumping sites. In the case of sugar beet pulp the energy consumption for drying and pelleting are 30 to 40% of the total energy used for beet processing (6). This process is only economical when done on a large scale and when energy costs are low. Other products, such as pectin and limonene, may be extracted from citrus peel. Pectin is used as a gelling agent in the food industry; limonene as a flavor compound. These are limited markets, and with increasing energy costs and alternative animal feed sources reducing the revenues from pectin-rich biomass for cattle feed sales, it is desirable to find new ways to convert this biomass to other useful products. This may be accomplished by microbial fermentation (16). Genetically modified bacteria have been used to produce ethanol from pectin-rich biomass (5, 7). Using genetically modified fungi, D-galacturonic acid has been converted to galactaric acid...

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Evolution of a recombinant (gucoamylase‐producing) strain of Fusarium venenatum A3/5 in chemostat culture

Cited by 23 publications

References 45 publications

Production of scopularide A in submerged culture with Scopulariopsis brevicaulis

Production of scopularide A in submerged culture with Scopulariopsis brevicaulis

Lipid production in batch and fed-batch cultures of Rhodosporidium toruloidesfrom 5 and 6 carbon carbohydrates

Engineering Filamentous Fungi for Conversion of d -Galacturonic Acid to l -Galactonic Acid

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