Use of photocatalytic reduction to hasten preparation of culture media for saccharolytic Clostridium species
Braz. j. microbiol
; 34(1): 22-26, Jan.-Apr. 2003. ilus, graf
Article
in English
| LILACS
| ID: lil-344560
Responsible library:
BR32.1
ABSTRACT
Cysteine is the preferred reducing agent used in the preparation of culture media for the growth of many strictly anaerobic microorganisms; however, redox potential reduction of cysteine is very slow, making it inconvenient if the medium is needed immediately or in large quantity. The time required to reduce culture medium containing resazurin (an indicator of reducing conditions) was dramatically shortened when the medium, after being injected with the reducing agent cysteine, was irradiated with incandescent light from a halogen lamp. Light intensity had an effect upon reduction time tubes kept in the dark took more than 12 h to achieve the desired degree of anaerobiosis (measured spectrophotometrically by the bleaching of the indicator, resazurin) while tubes subjected to ordinary laboratory illumination were reduced in about 2 h. When exposed to maximum light intensity (equivalent to a regular 100 watt bulb lamp) tubes could be made anaerobic in less than 20 min. Cysteine was essential for the bleaching of resazurin. Evidence that adequate anaerobiosis was achieved by light irradiation was provided by the fact that four Clostridium strains and one Thermoanaerobacter strain displayed similar growth (measured by lag time, growth rate, and extent of growth) in media reduced under high intensity light or under normal laboratory illumination.
Full text:
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Collection:
International databases
Database:
LILACS
Main subject:
In Vitro Techniques
/
Culture Media
/
Anaerobiosis
/
Light
Language:
English
Journal:
Braz. j. microbiol
Journal subject:
Microbiology
Year:
2003
Document type:
Article
Affiliation country:
Brazil
/
United States
Institution/Affiliation country:
U. S. Dairy Forage Research Center/US
/
Universidade de São Paulo/BR
/
University of North Texas/US