General characteristics of Yeast

General characteristics of Yeast

  • Yeast is basically chemorganotrophs as they can use the inorganic chemical as a source of energy.
  • Mostly yeast isolated from the surfaces of fruit and berries like apple, peaches and exudates from plants such as plants saps or cacti.
  • Yeast can be present in the gut flora of mammals and some insects and even in the deep-sea environment.
  • Yeast mostly grows at a temperature ranging between 20 to 28 degree Celsius at an acidic pH of 3.5 to 4.
  • For maintenance and preservation of yeast culture slant with 2%, caco3 can be used.
  • Classification of yeast can be done using its morphological characteristics, cultural characteristics and sexual characteristics and physiological characteristics.

Morphological characteristics:-

  • The characteristics of vegetative reproduction and a vegetative cell can be used to classify yeast.
  • Vegetative reproduction is done either by fission or by budding or by the formation of conidia.
  • Reproduction by fission is a typical characteristic of endomycetacea.
  • Morphology of the vegetative cells cultivated in liquid and solid media is founded on whether the cells are spherical, ovoid, cylindrical etc.

 Cultural characteristics:-

General characteristics of Yeast

  • Yeast grown in watery media may result in the formation of residue a ring, a pellicle.
  • Pellicle formation on a watery medium is a product associated with oxygen demand of yeast.
  • Growth on solid media may be either butyrous, friable, pigmented.
  • Lipomyces shows characteristics of mucoid growth.

Physiological characteristics:-

  • Yeast developing on a carbon source must either be able to format it or utilise it by respiration.
  • It has been found that when yeast utilises carbon source fermentatively it is also able to utilise it oxidatively.
  • The ability or inability to ferment carbohydrates to ethanol and carbon dioxide is the most important for differentiating spaces.
  • Variety of sugars is formatted by a variety of yeast.
  • Nitrogen metabolism is the fundamental feature of development the ability or inability to utilise various derivations of nitrogen can be made use of in classifying yeast.
  • The use of the ability or inability to grow in a synthetic medium devoid of vitamins like biotin and folic acid, inositol etc.
  • Except for genus saccharomyces which only grows in media containing certain east or protein hydrolysates all yeast can utilise a variety of nitrogen sources.
  • Practically every yeast uses urea at low concentration as a single source of nitrogen contributed that a sufficient amount of vitamins are supplied.
  • Fermentative yeast from a variety of oysters is varying amounts.
  • Ethyl acetate has been found to be the commonest and the most readily detectable Easter formed by yeast.
  • It is approved that the potential of yeast to soften gelatin is a very restricted taxonomic importance as very few are strongly proteolytic.

Sexual characteristics:-

  • Sexual characteristics involve the presence of the mode of ascus formation is characteristic of homothallic species.


General characteristics of Yeast