A novel strain of &amp;lt;i&amp;gt;Trichoderma viride&amp;lt;/i&amp;gt; shows complete lignocellulolytic activities

Kannan Neethu,V N Jisha,Sailas Benjamin,S Pradeep,S Sajith,M Rubeena,M K Sarath Josh,Prakasan Priji,K N Unni,S Sreedevi

doi:10.4236/abb.2012.38142

A novel strain of &lt;i&gt;Trichoderma viride&lt;/i&gt; shows complete lignocellulolytic activities

Kannan Neethu, V N Jisha + Show 8 more

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https://doi.org/10.4236/abb.2012.38142

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Abstract

In this study we describe a novel dark-green strain of Trichoderma viride exhibiting complete ensemble of cellulase, hemicellulase and ligninase activities on specific plate assays. To assess the cellulase production in detail, basal salt medium (BSM) was fortified with synthetic (carboxymethyl cellulose (CMC), glucose, sucrose, dextrose, lactose or maltose) and natural (flours of banana, banana peel, jack seed, potato or tapioca) carbon as well as nitrogen (yeast extract, beef extract, peptone, NaNO3 or NH4NO3) sources. Temperature and pH optima were 28°C and 4, respectively for the growth of the fungus in CMC-BSM with 137 U/mL cellulase activity, which was enhanced to 173 U/mL at 1.25% CMC concentration. Flours of potato and banana peel supported comparable yields of cellulase to that of CMC, while sodium nitrate was the preferred nitrogen source. The water soluble bluish-green pigment (a probable siderophore) extracted from the spores showed an absorption maximum at 292 nm. To sum up, the complete lignocellulolytic potential of this fungus offers great industrial significance, coupled with the production of a new pigment.

Highlights

Lignocellulosic biomass comprises cellulose, hemicellulose and lignin, of which lignin is the most recalcitrant to biodegradation and only higher fungi are capable of degrading this polymer via an oxidative process involving an array of oxidases, peroxidases and hydrolytic enzymes [1,2]
Hemicellulose and lignin form structures called microfibrils, which are organized into macrofibrils that mediate structural stability in the plant cell wall [2]
Insoluble and crystalline polysaccharide consisting of D-glucose residues linked by β-1, 4-glucosidic bonds; owing to its highly ordered crystalline structure, cellulose is more resistant to hydrolysis than hemicellulose

Summary

Introduction

Lignocellulosic biomass comprises cellulose, hemicellulose and lignin, of which lignin is the most recalcitrant to biodegradation and only higher fungi are capable of degrading this polymer via an oxidative process involving an array of oxidases, peroxidases and hydrolytic enzymes [1,2]. Hemicellulose and lignin form structures called microfibrils, which are organized into macrofibrils that mediate structural stability in the plant cell wall [2]. Hemicellulose macromolecules are often polymers of pentoses (xylose and arabinose), hexoses (mostly mannose) and a number of sugar acids, while cellulose is a homogenous polymer of glucose [3]. Glucose from the hydrolysis of cellulose can be fermented to useful industrial products such as ethanol, lactic acid, single cell protein and other value-added products [4]. There are different methods for the production of lowcost enzymes by the activity of microorganisms

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