Non-Synthetic media or complex media

 Non-Synthetic media or complex media:

*  Non synthetic medias are those whose exact chemical composition is not known.

* This is the usual culture media used by the bacteriologists for cultivation of microorganisms in the laboratory.

* It is practically impossible to prepare two identical sets of the same medium from differect batches of the same ingredients.

* Some of the ingredients used in these media are beef extract, Yeast extract, Peptones, blood, serum, casein hydrolysate etc.

* It can support the growth of wide variety of bacteria and other organisms.

* There-fore, it is employed as a routine culture media for growth of heterotrophs having none or little growth requirements.

* For examples , the complex medium used to grow either Escherichia coli or Leuconostoc mesenteroides is a follows:

Glucose                                   15g

Yeast extract                            5g

Peptone                                    5g

KH2PO4                                           2g

Distilled                                   1,000ml

pH                                            7.0

* Non- synthetic media often employ digests of casein (milk protein), soybeans, beef, yeast cells or any of a number of highly nutritions but chemically underfined substances.

* Such digets are available commercially in powdered form and can be weighed out rapidly and dissolved in distilled water to prepare a medium.