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Journal ArticleDOI

Analysis of factors responsible for the regeneration to intact cells from sphaeroplasts of Saccharomyces cerevisiae

01 Jan 1994-Bioprocess Engineering (Springer-Verlag)-Vol. 10, Iss: 1, pp 15-20
TL;DR: The regeneration of Saccharomyces cerevisiae cells from its sphaeroplasts were found to be influenced by a number of factors, including malt-extractglucose-yeast extract-peptone medium and growth medium.
Abstract: The regeneration of Saccharomyces cerevisiae, NCIM 3288, cells from its sphaeroplasts were found to be influenced by a number of factors. The most suitable conditions of regeneration were also dependent on growth medium, that is, using malt-extractglucose-yeast extract-peptone (MGYP) medium: mannitol 0.7 M, pH 6.5, 30 °C and using yeast extract-peptone-glucose (YPG) medium: sucrose 0.7 M, pH 5.0 and 30 °C. The maximum regeneration frequency was observed in YPG medium.
Citations
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Journal ArticleDOI
TL;DR: An attempt to produce ethanol from a cellulosic substrate by a single-stage process using intergeneric hybrids obtained from Trichoderma reesei QM 9414 and Saccharomyces cerevisiae NCIM 3288 fusants is described, showing the highest synthesis of ethanol from filter paper cellulose.

10 citations

Journal ArticleDOI
01 Jan 2012
TL;DR: In this article, the ability of Rhizopus oryzae and rhizopus microsporus strains to produce fumaric acid on glycerol as the sole carbon source in the medium was evaluated.
Abstract: Rhizopus oryzae and Rhizopus microsporus strains were screened for their ability to produce fumaric acid on glycerol as the sole carbon source in the medium. After seven days of stationary culture, fumaric acid was assayed by HPLC analysis, and maximum concentrations of 0.3% (w/v) and 0.33% (w/v) were recorded. Protoplast fusion was used to improve fumaric acid production. A selective medium for the fusant culture was composed on the basis of biochemical differences between parental strains, as examined using the Biolog FF MicroPlate TM Fungi Identification Test. Double fusion rounds led to a 1.46-fold increase in fumaric acid productivity relative to the parental strains. Individual Rhizopus fusants demonstrated a various ability to produce fumaric acid from 2.0% (w/v) of glycerol, with the most effective ones producing from 0.2 to 0.27 g@ g !1 of this acid. To date, no studies have been carried out to improve fumaric acid production by Rhizopus with the use of glycerol as the only carbon source in the medium.

10 citations

Journal Article
TL;DR: Individual Rhizopus fusants demonstrated a various ability to produce fumaric acid from 2.0% (w/v) of glycerol, with the most effective ones producing from 0.2 to 0.27 g@ g !
Abstract: Rhizopus oryzae and Rhizopus microsporus strains were screened for their ability to produce fumaric acid on glycerol as the sole carbon source in the medium. After seven days of stationary culture, fumaric acid was assayed by HPLC analysis, and maximum concentrations of 0.3% (w/v) and 0.33% (w/v) were recorded. Protoplast fusion was used to improve fumaric acid production. A selective medium for the fusant culture was composed on the basis of biochemical differences between parental strains, as examined using the Biolog FF MicroPlate TM Fungi Identification Test. Double fusion rounds led to a 1.46-fold increase in fumaric acid productivity relative to the parental strains. Individual Rhizopus fusants demonstrated a various ability to produce fumaric acid from 2.0% (w/v) of glycerol, with the most effective ones producing from 0.2 to 0.27 g@ g !1 of this acid. To date, no studies have been carried out to improve fumaric acid production by Rhizopus with the use of glycerol as the only carbon source in the medium.

9 citations

References
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Journal ArticleDOI
TL;DR: The most suitable conditions for protoplasting were as follows: age of the organism in slant, 3 days; mycelium age, 20 h; volume of lytic enzymes, 190 ml;Mycelial weight (dry equivalent), 1.66 g; time of contact with lytic enzyme, 2 h; temperature of protoplasts, 30°C; phosphate buffer, 25 m m , pH 6.5; KCl as osmotic stabilizer, 0.7 m

43 citations

Journal ArticleDOI

32 citations


"Analysis of factors responsible for..." refers background in this paper

  • ...In get matrices, having gelatin on agar, structurally and functionally efficient cell wall is synthesised [4, 5 ]. Also, some species of the yeast may regenerate cell walls in liquid medium....

    [...]

Journal ArticleDOI
TL;DR: Protoplast viability was studied in osmotic stabilizer supplemented with glucose or glutamine and protein synthesis, as measured by 3H-lysine uptake, matched the viability profile determined by fluorescence microscopy.
Abstract: Factors affecting high yields, regeneration frequencies, and viability of protoplasts from clonal cultures of Microsporum gypseum were investigated. Maximum yields of protoplasts were obtained after 6 hrs digestion of 2–4 days old mycelium with Novozyme 234 using CaCl2 (0.4 M) as an osmotic stabilizer and glycine + HCl (pH 4.5) as the buffer system. Mercaptoethanol + dithiothreitol (0.01 M) proved to be the best pretreatment of mycelium prior to digestion with enzyme. A regeneration frequency of 94.4% was obtained using the top agar method with complete medium (pH 6.5) containing 0.5% agar and 0.4 M CaCl2 as an osmoticum. Colonies from regenerated protoplasts on medium containing CaCl2 were pigmented and completely powdery with high sporulation. Protoplast viability was studied in osmotic stabilizer supplemented with glucose or glutamine. After 24 hrs, glucose (2%) and glutamine (2%) enhanced protoplast viability by 22% and 23%, respectively. Protein synthesis, as measured by 3H-lysine uptake, matched the viability profile determined by fluorescence microscopy.

19 citations

Journal ArticleDOI
TL;DR: By protoplast fusion a modified flocculent strain was obtained with higher specific activity of alcohol dehydrogenase (ADH I) and an enhanced production of glycerol compared with the wild-type strain.
Abstract: Experiments were performed to investigate growth, ethanol and glycerol production by wild-type strains (RHO) and respiratory-deficient (rho) mutants of Saccharomyces cerevisiae. Furthermore protoplasts were fused in order to enhance the fermentation capacity of a flocculent strain. At high substrate conditions, 150 g/l of saccharose, there is no difference in cell growth. However, at a glucose concentration of 10–20 g/l the mutants grow much slower. After 3 days of incubation at 28° C in a complete medium the viability of the two strains is the same. In minimal medium on the other hand the number of viable cells of the mutant is 100-fold reduced. All mutants tested showed a higher specific activity of alcohol dehydrogenase (ADH I) and an enhanced production of glycerol compared with the wild-type strain. By protoplast fusion a modified flocculent strain was obtained with higher specific activity of ADH I and a reduced biosynthesis of glycerol. However, the yields of ethanol (75–78%) are about the same for the wild-type strain and the rho mutants under aerobic conditions in absence of catabolite repression.

15 citations

Book ChapterDOI
TL;DR: This review is concerned with the nature and application of the new methods to the genetic manipulation of yeasts for strain improvement and the study of molecular and cellular biology.
Abstract: Yeasts are fungi that exist predominantly in the unicellular state. The study of yeasts has contributed much to our knowledge of cellular and molecular biology. In addition, these lower eukaryotes are an extremely important group of industrial micro-organisms. Of particular importance is the yeast Saccharomyces cerevisiae, which is used in the baking, brewing and alcohol production industries. The breeding of industrial yeasts to meet both product and process requirements is currently an active area of research. The techniques available for yeast strain improvement include the traditional methods of sexual hybridization and mutagenesis, and the new procedures of protoplast fusion and transformation. This review is concerned with the nature and application of the new methods to the genetic manipulation of yeasts for strain improvement and the study of molecular and cellular biology.

15 citations