Abstract - Physiological, morphological, and mannanase production studies on Aspergillus niger uam-gs1 mutants

Physiological, morphological, and mannanase production studies on Aspergillus niger UAM-GS1 mutants

Soledad De Nicolás-Santiago
Departamento de Biotecnología
Universidad Autónoma Metropolitana-Iztapalapa
Av. San Rafael Atlixco 186, Iztapalapa
09340 México D.F., México
Tel: 52 55 58044999
Fax: 52 55 58044712
E-mail:sol@xanum.uam.mx

Carlos Regalado-González
DIPA, PROPAC
Facultad de Química
Universidad Autónoma de Querétaro
CU. Cerro de las Campanas S/N
76010 Querétaro, Qro. México
Tel/Fax: 52 442 1921304E-mail: carlosr@uaq.mx

Blanca García-Almendárez
DIPA, PROPAC
Facultad de Química
Universidad Autónoma de Querétaro
CU. Cerro de las Campanas S/N
76010 Querétaro, Qro. México
Tel/Fax: 52 442 1921304
E-mail: blancag@uaq.mx

Francisco J. Fernández-Perrino
Departamento de Biotecnología
Universidad Autónoma Metropolitana-Iztapalapa
Av. San Rafael Atlixco 186, Iztapalapa
09340 México D.F., México
Tel: 52 55 58046453
Fax: 52 55 58044712
E-mail: fjfp@xanum.uam.mx

Alejandro Téllez-Jurado
Departamento de Biotecnología
Universidad Politécnica de Pachuca
Ex-Hacienda de Sta. Bárbara
Carretera Pachuca-Cd. Sahagún, km. 20
Zempoala, Hidalgo, Mexico
Tel/Fax: 52 743 7911800
E-mail: alito@upp.edu.mx

Sergio Huerta-Ochoa*
Departamento de Biotecnología
Universidad Autónoma Metropolitana-Iztapalapa
Av. San Rafael Atlixco 186, Iztapalapa
09340 México D.F., México
Tel: 52 55 58044999
Fax: 52 55 58044712
E-mail: sho@xanum.uam.mx

*Corresponding author

Financial support: Universidad Autónoma Metropolitana –Iztapalapa, México.

Mutant strains from Aspergillus niger UAM-GS1 were produced by UV radiation to increase their hemicellulolytic and cellulolytic activity production. The mutant strains showing more enzymatic activity were those labelled GS1-S059 and GS1-S067. These strains also showed the largest relationship between diameter of hydrolysis zone and colony diameter. The mutant GS1-S067 showed a colony radial extension rate and a biomass growth rate [g biomass/(cm² h)], 1.17 times higher than that achieved by strain UAM-GS1. The high invasive capacity makes this mutant strain a promising alternative for its use in solid substrate fermentation(SSF). The morphological properties of the two mutant strains were evaluated by using scanning electron microscopy. The diameter of the sporangium of the mutant strains GS1-S059 and GS1-S067 was significantly larger (P < 0.05) than that found for the parental strain. The hypha length and diameter of the mutant strains significantly changed (P < 0.05) compared to the parental strain. A Pearson correlation analysis on hypha length, sporangium diameter, and cellulose and xylanase activities indicated that there was a strong relationship among these variables in relation to mannanase activity. Mutant strains GS1-S059 and GS1-S067 significantly increased their level of mannanase, xylanase and cellulase production, compared to the parental strain, improving their potential industrial applications.