Algorithm-based design of novel synthetic media for Metarhizium anisopliae simulating its nutritional conditions in the environment.
OBJECTIVE
The objective of this study was to develop a novel synthetic growth medium for increased conidium production of the entompathogenic fungus Metarhizium anisopliae. The medium should simulate natural nutritional conditions.


RESULTS
Macro- and micronutrients were selected in concentrations found in insects or from sources which are believed to be advantageous for virulence. Medium development was guided by a problem-oriented genetic algorithm (GA) implemented with 'mutation' and 'recombination' operators specific for this optimization problem. Following five optimization steps and a total of 181 medium variations, 19 synthetic media led to increased conidium production as compared with the standard Sabouraud dextrose agar medium: increases in conidia yields of up to 120% and a 17-fold higher conidium production per square centimetre of mycelium were achieved. Rapid germination of conidia, conidial C : N ratio, as well as spore-bound Pr1 protease production were monitored as proposed quality control markers for a virulent inoculum.


CONCLUSIONS
It was demonstrated that our problem-oriented GA is a powerful tool for the design of chemically defined cultivation media with special/enhanced properties for anamorphic fungi.


CONCLUSIONS
This is the first study, which demonstrates the advantage of the use of a GA for the rapid design of solid synthetic media for maximum production of virulent conidia.
Hutwimmer
S
S
Institute of Microbiology, University of Innsbruck, Innsbruck, Austria. Stefan.hutwimmer@uibk.ac.at
Wagner
S
S
Affenzeller
M
M
Burgstaller
W
W
Strasser
H
H
D000465:Algorithms; D003470:Culture Media; D005502:Food; D052981:Metarhizium / Q000254:growth & development*; D008957:Models, Genetic; D009172:Mycology / Q000379:methods*; D012988:Soil Microbiology
D003470:Culture Media