Mutagenesis and Analysis of Mold Aspergillus niger for Extracellular Glucose Oxidase Production Using Sugarcane Molasses

Abstract

Aspergillus niger ORS-4.410, a mutant of A. niger ORS-4, was generated by repeated ultraviolet (UV) irradiation. Analysis of the UV treatment dose on wild-type (WT) A. niger ORS-4, conidial survival, and frequency of mutation showed that the maximum frequency of positive mutants (25.5%) was obtained with a 57% conidial survival rate after the second stage of UV irradiation. The level of glucose oxidase (GOX) production from mutant A. niger ORS-4.410 thus obtained was 149% higher than that for WT strain A. niger ORS-4 under liquid culture conditions using hexacyanoferrate (HCF)-treated sugarcane molasses (TM) as a cheaper carbohydrate source. When subcultured monthly for 24 mo, the mutant strain had consistent levels of GOX production (2.62 +/- 0.51 U/mL). Mutant A. niger ORS-4.410 was markedly different from the parent strain morphologically and was found to grow abundantly on sugarcane molasses. The mutant strain showed 3.43-fold increases in GOX levels (2.62 +/- 0.51 U/mL) using HCF-TM compared with the crude form of cane molasses (0.762 +/- 0.158 U/mL).

Biocontrol of tomato plant diseases caused by Fusarium solani using a new isolated Aspergillus tubingensis CTM 507 glucose oxidase

“…The latter were screened for GOD enzyme production. Initially, the isolates were incubated in a solid screening medium at 30 8C for 72 h. After the fungal growth, a solution containing 20 mM sodium phosphate buffer, pH 7.0, 0.1 M glucose, and 20 mg/ mL of horseradish peroxidase (HRP) were added [21]. Then, the diameter of the brownish-red halos around the fungi (D) and the diameter of the fungal growth (d) were measured.…”

“…The pH was adjusted to 5.0 and the medium was supplemented with chloramphenicol (0.1 g/L) to inhibit bacterial growth; the solid screening medium used for the preliminary selection of GOD producing strains, contains 10 g/L of glucose, 6 g/L of NaNO 3 , 0.5 g/L of KCl, 0.5 g/L of MgSO 4 Á7H 2 O, 1.5 g/L of KH 2 PO 4 with traces of CuSO 4 , ZnSO 4 , MnCl 2 and FeSO 4 , 20 g of agar and 2.5 mM o-dianisidine [21]; the liquid medium used for GOD production contains 10 g/L of glucose, 1 g/L of peptone from casein, 5 g/L of yeast extract, 6 g/L of NaNO 3 , 0.5 g/L of KCl, 0.5 g/L of MgSO 4 Á7H 2 O, 1.5 g/L of KH 2 PO 4 with traces of CuSO 4 , ZnSO 4 , MnCl 2 and FeSO 4 [21]; Potato Dextrose Agar (PDA, Oxoid, Johannesburg) was used for pre-growing the new isolated fungi GOD production and the pathogen F. solani [24]; the tryptone salt medium utilized for the storage of the pathogen F. solani contains 1 g/L of tryptone, 8.5 g/L of NaCl, 1% of Tween 20, and 15% of glycerol [24].…”

Enhanced production and characterization of a novel -D-glucose:oxygen-1-oxidoreductase by using Aspergillus niger UV-180-C mutant strain

“…The curve presented 81.41% killing rate while the survival rate was 18.58% (Figures 1 and 2). The conidial killing of 43% and survival of 57% has been reported after ultraviolet treatment of A. niger (Singh, 2006).…”

“…A noticeable increase in activity of mutant strain was observed on using corn steep liquor (2%). Singh, (2006) observed the glucose oxidase activity of 2.62 U/mL by using molasses as a carbon source for UV mutant strain of A. niger. Upon using sucrose as carbon source, Semashko et al (2004) obtained 8.23 U/mL glucose oxidase activities from mutant strain of P. funiculosum.…”

“…The overall production of glucose oxidase from A. niger UV-180-C was increased by 3.53 fold after optimization of fermentation conditions. Singh (2006) reported the 3.43 fold increase in glucose oxidase production using UV mutant of A. niger.…”