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Invertase production on solid-state fermentation by Aspergillus niger strains improved by parasexual recombination
Alba Mónica Montiel-González1, Francisco José Fernández, Gustavo Viniegra-González
1Department of Biotechnology, Universidad Autónoma Metropolitana-Iztapalapa, Mexico DF, México.
Applied Biochemistry and Biotechnology
|October 25, 2002
Summary
Parasexual crosses in Aspergillus niger significantly enhanced invertase production. Diploid strains achieved 5-18 times higher enzyme yields in solid-state fermentation, offering improved industrial applications.
Area of Science:
- Biotechnology
- Microbial Genetics
- Enzyme Production
Background:
- Solid-state fermentation (SSF) offers higher enzyme yields than submerged fermentation for Aspergillus niger.
- Haploid mutant strains (Aw96-3, Aw96-4) demonstrated superior enzyme productivity over the wild-type (A. niger C28B25).
Purpose of the Study:
- To enhance invertase productivity in Aspergillus niger using parasexual crosses.
- To evaluate the performance of diploid and autodiploid strains in solid-state fermentation.
Main Methods:
- Parasexual crosses were performed on haploid auxotrophic mutants of Aspergillus niger.
- Diploid (DAR2) and autodiploid (AD96-4) strains were isolated via mutation complementation.
- Invertase production was quantified in solid-state fermentation using polyurethane foam at a water activity of 0.96.
Main Results:
- Diploid strains exhibited 5-18 fold higher invertase productivity compared to haploid strains.
- Specific productivity values: C28B25 (441), Aw96-3 (254), Aw96-4 (62), DAR2 (1324), and AD96-4 (2677 IU/(L x h)).
- The autodiploid strain AD96-4 showed the highest invertase yield.
Conclusions:
- Genetic recombination via parasexual crosses effectively improves Aspergillus niger strains for enzyme production.
- Enhanced strains hold significant potential for optimizing industrial solid-state fermentation processes.