Fungal co-culture increases ligninolytic enzyme activities: statistical optimization using response surface methodology

Abstract

The optimization of ligninolytic enzyme (LE) activities in a novel fungal co-culture between Pycnoporus sanguineus and Beauveria brongniartii were studied using a Plackett–Burman experimental design (PBED) and a central composite design (CCD). In addition, H₂O₂ role was analyzed. Laccase (EC. 1.10.3.2) and MnP (EC 1.11.1.14) activities of P. sanguineus increased 6.0- and 2.3-fold, respectively, in the co-culture with B. brongniartii. The H₂O₂ content was higher in the co-culture (0.33–7.12-fold) than in the P. sanguineus monoculture. The PBED revealed that yeast extract (YE), FeSO_4, and inoculum amount were significant factors for laccase and MnP activities and H₂O₂ production in the co-culture, which increased by 8.2-, 5.2- and 1.03-fold, respectively. The YE and FeSO₄ were studied using a CCD to optimize the studied response variables. Laccase activity was enhanced 1.5-fold by CCD, the optimal amount of YE was 0.366 g L⁻¹. Quadratic term of FeSO₄ modulated MnP activity and was associated with a 4.28-fold increase compared to the PBED. Both YE and its quadratic term significantly affected H₂O₂ production; however, the CCD did not enable an increase in H₂O₂ production. Pearson correlation indicated an increase in laccase (r²=0.4411, p = 0.0436) and MnP (r²=0.5186, p = 0.0198) activities following increases in H₂O₂ in the co-culture system.

Keywords:

• Experimental design
• fungal interaction
• laccase
• manganese peroxidase

Disclosure statement

The authors declare no commercial or financial conflict of interest.

Additional information

Funding

The authors are grateful for the funding of the project “Mechanism of increasing ligninolytic enzyme activities of fungal co-cultures between white rot fungi and soil borne micromycetes” by the University of California Institute for Mexico and the United States (UC MEXUS-CONACyT).