Changes in the physiological properties and kinetics of citric acid accumulation via carbon ion irradiation mutagenesis of Aspergillus niger

Abstract

Abstract:The objective of this work was to produce citric acid from corn starch using a newly isolated mutant of Aspergillus niger, and to analyze the relationship between changes in the physiological properties of A. niger induced by carbon ion irradiation and citric acid accumulation. Our results showed that the physiological characteristics of conidia in A. niger were closely related to citric acid accumulation and that lower growth rate and viability of conidia may be beneficial to citric acid accumulation. Using corn starch as a raw material, a high-yielding citric acid mutant, named HW2, was obtained. In a 10-L bioreactor, HW2 can accumulate 118.9 g/L citric acid with a residual total sugar concentration of only 14.4 g/L. This represented an 18% increase in citric acid accumulation and a 12.5% decrease in sugar utilization compared with the original strain.

Changes in transcript levels of starch hydrolysis genes and raising citric acid production via carbon ion irradiation mutagenesis of Aspergillus niger

“…Heavy ion mutagenesis is a powerful and high-efficient tool that has been readily applied in mutagenesis of bacteria, fungi and microalgae [ 29 ]. Compared with low-LET (about 0.2-5KeV/μ) mutation induction techniques (X-rays or ɣ-rays)[ 30 , 31 ], high-LET heavy ion beams can cause double-strand DNA break [ 32 ] owing to denser ionization along their trajectories, which induced different types of DNA damage, such as, translocations, inversions, insertion, and DNA deletions, which would be valuable for obtaining diverse phenotypic microbial mutants for functional genes research.…”

Ácido Cítrico: Um Enfoque Molecular

“…É conhecido que a fonte de carbono e de fosfato mais adequada para a produção do ácido cítrico, são a sacarose e o fosfato de potássio monobásico, respectivamente (FOSTER, 1949;GREWAL et al, 1995;RODRIGUES, 2006;PASTORE et al, 2011). O fungo A. niger é amplamente descrito na literatura para a produção de ácido cítrico (RODRIGUES, 2006;AUTA et al, 2014;HU et al, 2014;HU et al, 2016). Porém,…”

Recent Progresses on Industrialization of Sweet Sorghum at IMP

“…10; Based on these results, Chen et al (2010) screened high-producing-avermetin-Bla strain ZJAV-Y203 from the original strain Streptomyces avermitilis (ZJAV-A1) irradiated by carbon ion beam with different doses, the Bla component increased by 51.43%. In recent years, a high-yielding citric acid mutant, HW2, was obtained from Aspergillus niger induced by carbon ion irradiation which can accumulate 118.9 g/L citric acid with a residual total sugar concentration of only 14.4 g/L in a 10-L bioreactor (Hu et al, 2016). Zhou et al (2016) investigated the utility of two rounds of heavy ion beam irradiation to create Clostridium tyrobutyricum mutants with improved bioproduction capability under acidic conditions and revealed that carbon ions effectively induced the expression of key enzymes in glycolysis, product formation, energy and redox metabolism and the cellular response to butyric acid production.…”