Mutagenesis and analysis of mold Aspergillus niger for extracellular glucose oxidase production using sugarcane molasses.
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).
Singh
O V
OV
Department of Biotechnology, Indian Institute of Technology, Roorkee-247 667, India. ovsll@yahoo.com
D001234:Aspergillus niger / Q000201:enzymology / Q000235:genetics* / Q000648:ultrastructure; D001709:Biotechnology / Q000379:methods*; D002241:Carbohydrates / Q000737:chemistry; D005285:Fermentation; D015971:Gene Expression Regulation, Enzymologic; D015966:Gene Expression Regulation, Fungal; D005949:Glucose Oxidase / Q000096:biosynthesis* / Q000737:chemistry / Q000378:metabolism; D008855:Microscopy, Electron, Scanning; D008965:Molasses; D016296:Mutagenesis; D009154:Mutation; D031786:Saccharum; D014466:Ultraviolet Rays
D002241:Carbohydrates; D005949:Glucose Oxidase