CHU 13 medium is a culture medium used in

microbiology Microbiology () is the scientific study of microorganisms, those being unicellular (single cell), multicellular (cell colony), or acellular (lacking cells). Microbiology encompasses numerous sub-disciplines including virology, bacteriology, prot ...

for the growth of certain

algal Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular mic ...

species, first published by S.P. Chu in 1942. It is used as growth medium for the

biofuel Biofuel is a fuel that is produced over a short time span from biomass, rather than by the very slow natural processes involved in the formation of fossil fuels, such as oil. According to the United States Energy Information Administration (E ...

candidate alga ''

Botryococcus braunii ''Botryococcus braunii'' is a green, pyramid-shaped planktonic microalga that is of potentially great importance in the field of biotechnology. Colonies held together by a lipid biofilm matrix can be found in temperate or tropical oligotrophic l ...

''.C. Largeau, E. Casadevall, C. Berkaloff and P. Dhamelincout (1980) Phytochemistry, 19, 1943. Botryococcus braunii

CHU 13 includes essential minerals and trace

elements Element or elements may refer to: Science * Chemical element, a pure substance of one type of atom * Heating element, a device that generates heat by electrical resistance * Orbital elements, parameters required to identify a specific orbit of ...

that are required by algae for growth, but does not include a carbon source and so is only appropriate for growth of phototrophs. It can be prepared as either a liquid medium or as an

agar Agar ( or ), or agar-agar, is a jelly-like substance consisting of polysaccharides obtained from the cell walls of some species of red algae, primarily from ogonori (''Gracilaria'') and "tengusa" (''Gelidiaceae''). As found in nature, agar is ...

medium. The remaining volume is pure,

de-ionized water Purified water is water that has been mechanically filtered or processed to remove impurities and make it suitable for use. Distilled water was, formerly, the most common form of purified water, but, in recent years, water is more frequently puri ...

. Because it is difficult to weigh out some of the trace minerals, it is advisable to create a mixture of all components at a large concentration, such as a thousand times these measures, and then mix with the appropriate amount of (pure, de-ionized) water. Correct pH to 7.5, and then autoclave.

References

Microbiological media Algaculture {{Microbiology-stub