Beauveria Bassiana Amylase-Polygalacturonase Production Using Lignocellulosic Biomass and Application in Juice Processing

Document Type : Research Paper


Department of Biotechnology and Food Science, Faculty of Applied Sciences, Durban University of Technology, P O Box 1334, Durban, 4000, South Africa.


Background: The search for sources of industrial biocatalysts, which are non-pathogenic and can utilise cheap nutrient
sources, has been a continuous endeavour in the ~ 7 billion USD enzyme industry. Beauveria bassiana, an endophytic
fungal entomopathogen, is non-pathogenic and possesses the potential to secrete various bioproducts while utilising
readily available lignocellulosic biomass.

Objective:  This study investigated the optimised production of two glycosyl hydrolases, amylase and polygalacturonase,
by B. bassiana while utilising readily available agricultural residues. Subsequently, the industrial potential of the enzymes
in the clarification of fruit juice was evaluated.

Materials and Methods:Initially, seven agro residues were screened for the concomitant production of amylase and
polygalacturonase by B. bassiana SAN01. Subsequently, statistical optimisation tools, Plackett Burman Design (PBD)
and Central Composite Design (CCD), were employed for the optimisation of enzyme production. The enzyme mixture
was partially purified and applied in the clarification of pineapple juice.

Result: The production of B. bassiana SAN01 amylase and polygalacturonase was found to be maximal while utilising
wheat bran. Subsequent to PBD and CCD optimisation, the optimal conditions for enzyme production were identified to
be at 30 °C, pH 6.0 and wheat bran concentration of ~40 g.L-1. Under these optimised conditions, heightened production
levels of 34.82 and 51.05 U.mL-1 were recorded for amylase and polygalacturonase, respectively, which were 179% and
187% of the initial unoptimised levels. In addition, the most effective clarification of the juice (~90%) was observed at 35
°C after an incubation time of 120 min with no significant effect on the pH and total dissolved solids.

Conclusion: B. bassiana, a well-known biocontrol agent, was shown to produce amylase and polygalacturonase using
readily available agricultural residues for the first time. These enzyme production levels are the highest for these enzymes
from any known endophytic fungal entomopathogen. This study further demonstrates the potential applicability of B.
bassiana in other industrial processes besides its widespread use as a biopesticide.


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