MEDIA FOR ANAEROBIC GROWTH OF 

 PHOTOS YNTHE TIC BACTERIA 



SUBIR K. BOSE 



A large number of media, both semi-synthetic and synthetic, have 

 been described for growth of photosynthetic bacteria. Recipes are 

 constantly being modified (usually in some minor way) and, according- 

 ly, only a few media representative of those in common use are given 

 below. 



Anaerobic conditions are established by one of the three following 

 methods: (a) Growth in completely filled glass-stoppered reagent bot- 

 tles, (b) Growth in completely filled bottles (250 ml milk dilution, 1 

 liter Roux or 5.6 liter Diphtheria Toxin) which are sealed with a 1/2- 

 3/4 inch layer of sterile paraffin. Molten paraffin is poured directly 

 onto the medium and on cooling a plug forms in the neck of the bottle. 

 This method is particularly useful with gas-producing cultures, since 

 the plug loosens slightly and acts as an escape valve. The plug can be 

 kept in place with a strip of adhesive tape, (c) Growth under an oxygen- 

 free gas phase. 



Illumination is conveniently provided by banks of 60- watt, 120- volt 

 Lumiline lamps placed on both sides of the inoculated culture vessels, 

 A fan is ordinarily used to aid in dissipation of heat generated by the 

 lamps. 



NONSULFUR PURPLE BACTERIA 



These organisms are ordinarily grown with an organic carbon 

 source. Some types are capable of growing with carbon dioxide as the 

 primary carbon source if an "accessory donor" such as molecular 

 hydrogen and appropriate growth factors are provided (e,g., see 

 Ormerod and Gest, Bacteriol. Rev., 26, 51 (1962)), Depending on the 

 particular organic carbon source employed, carbon dioxide may also 

 have to be furnished (e,g,, with ethanol or butyrate). Malate is an ex- 

 cellent carbon source for many nonsulfur purples, and with this com- 

 pound, addition of carbon dioxide is unnecessary. In many instances, 

 other compounds such as succinate, fumarate or lactate can be sub- 

 stituted for malate with good results. Complex supplements such as 

 yeast extract frequently enhance growth rates, and there is little doubt 



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