Citric acid production by 2-deoxyglucose-resistant mutant strains of Aspergillus niger

Abstract

Many mutant strains showing resistance to 2-deoxy-D-glucose (DG) on minimal medium containing glycerol as a carbon source were induced from Aspergillus niger WU-2223L, a citric acid-producing strain. The mutant strains were classifiable into two types according to their growth characteristics. On the agar plates containing glucose as a sole carbon source, mutant strains of the first type showed good growth irrespective of the presence or absence of DG. When cultivated in shake cultures, some strains of the first type, such as DGR1-2, showed faster glucose consumption and growth than strain WU-2223L. The period for citric acid production shortened from 9 days for strain WU-2223L to 6-7 days for these mutant strains. The levels and yields of citric acid production of the mutant strains were almost the same as those of strain WU-2223L. The mutant strains of the second type, however, showed very slow or no growth on both the agar plates containing glucose and fructose as sole carbon sources. In shake cultures, mutant strains such as DGR2-8 showed decreased glucose consumption rates, resulting in very low production of citric acid.

Polyploid Formation Between Aspergillus niger and Trichoderma viride For Enhanced Citric Acid Production From Cellulose

“…3 Citric acid production by parental strains, A. niger Yang no.2, and T. viride M5S51, as compared to hybrid trains, AT 11-2-3, AT 11-2-4, and AT 11-2-10, using various carbon sources in semisolid culture presence of 1.0 g/l 2-deoxy-D-glucose (DG; data not shown). This result correlated with the previous studies indicating that DG-resistant mutants showed increased citric acid production using glucose and cellobiose as carbon sources [33][34][35].…”

Improvement of xylanase production by a parasexual cross between Aspergillus niger strains

“…These mutants were also less sensitive to carbon catabolic repression by glucose than the wild type strain A. niger C28B25. This observation was in agreement with some reports describing the isolation of 2DG-resistant strains which were also less sensitive to carbon catabolite repression (Kirimura et al, 1992;Gosh et al, 1991). In this report, we describe the enhancement of xylanase production in comparison to the wild type strain A. niger C28B25 achieved by a diploid strain, obtained by means of a parasexual cross between two of the mutants isolated by Antier et al (1993).…”

Citric acid and polyols production by Aspergillus niger at high glucose concentration in solid state fermentation on inert support

“…When 300 gill of glucose was used, citric acid accumulation stopped at 70 h and its concentration slowly decreased (Fig. Citric acid concentration (79 g/l) and productivity (1.13 g/1 h) were high as compared with those obtained in Iiquid cultures by Lee et al, (1989) with A. niger immobilized into polyurethane foam and with those obtained by Kirimura et al, (1992) with a hyper-producer of citric acid strain of A niger suggesting important influence of the SSF conditions. Consumption of citric acid under this conditions was not clear since glycerol concentration was high enough (Fig.…”