Assessments on the catalytic and kinetic properties of beta-glucosidase isolated from a highly efficient antagonistic fungus Trichoderma harzianum

• Main Authors: Khalili, E., Huyop, F., Javed, M. A., Mahat, N. A., Batumalaie, K., Abdul Wahab, R.
• Format: Article
• Language: English
• Published: Universidade Federal de Uberlandia 2018
• Subjects: QD Chemistry
• Online Access: http://eprints.utm.my/id/eprint/79701/1/RoswaniraAbdulWahab2018_AssessmentsontheCatalyticandKinetic.pdf; http://eprints.utm.my/id/eprint/79701/; http://dx.doi.org/10.14393/BJ-v34n1a2018-39384
• Institution: Universiti Teknologi Malaysia

Due to the toxicity and inefficiency of chemical fungicides to control infestation of Macrophomina phaseolina (Tassi) Goid which causes charcoal rot in plants, a biotechnological approach using β-glucosidase (EC.3.2.1) as the alternative bioactive ingredient in fungicide is hereby, proposed. The extracellular enzyme was isolated from a highly efficient fungal antagonist, Trichoderma harzianum T12. The highly similar molecular masses obtained using SDS-PAGE (96 kDa) and MALDI-TOF mass spectrometry (98.3 kDa) affirmed that the β-glucosidase was purified to homogeneity. Consequently, optimum catalytic parameters that rendered the highest enzyme activity were found to be: 45˚C, pH 7, inoculum size of 10 % (w/v), supplementation with metal ions Zn2+ and Mn2+ ions, and Tween 80. Addition of wheat bran and (NH4)2SO4 as carbon and nitrogen sources also improved enzyme activity. BLASTn showed the sequence of β-glucosidase T12 was highly identical to other β-glucosidases viz. T. harzianum strain IOC-3844 (99%), T. gamsii and T. virens bgl1 (86 %) as well as T. reesei strain SJVTR and T. viride strain AS 3.3711 (84 %). Kinetic assessment showed that β-glucosidase T12 catalyzes hydrolytic activity is characterized by a Km of 0.79 mM and Vmax of 8.45 mM min-1 mg-1 protein, with a corresponding kcat of 10.69 s-1.