A possible influence of extracellular polysaccharides on the analysis of intracellular metabolites from Trichoderma harzianum grown under carbon-limited conditions

Lucas Gelain,José Geraldo Da Cruz Pradella,Aline Carvalho Da Costa,Luuk Van Der Wielen,Walter M Van Gulik

doi:10.1016/j.funbio.2020.12.002

Abstract

Intracellular metabolites were evaluated during the continuous growth of Trichoderma harzianum P49P11 under carbon-limited conditions. Four different conditions in duplicate were investigated (10 and 20 g/L of glucose, 5.26/5.26 g/L of fructose/glucose and 10 g/L of sucrose in the feed). Differences in the values of some specific concentrations of intracellular metabolites were observed at steady-state for the duplicates. The presence of extracellular polysaccharide was confirmed in the supernatant of all conditions based on FT-IR and proton NMR. Fragments of polysaccharides from the cell wall could be released due to the shear stress and since the cells can consume them under carbon-limited conditions, this could create an unpredictable carbon flow rate into the cells. According to the values of the metabolite concentrations, it was considered that the consumption of those fragments was interfering with the analysis.

Highlights

The quantitative analysis of metabolites is a prerequisite for metabolic engineering (Buchholz et al, 2001), which can be applied to create an optimal strain to produce desired products
The production of extracellular polysaccharides by T. harzianum P49P11 was discovered in this work and their presence in the growth medium could be interfering with the analysis
Intracellular metabolites were analysed during the cell growth of T. harzianum P49P11 using different limiting carbon sources

Summary

Introduction

The quantitative analysis of metabolites is a prerequisite for metabolic engineering (Buchholz et al, 2001), which can be applied to create an optimal strain to produce desired products. Studies to evaluate the quantitative analysis of metabolites employing T. harzianum P49P11 is the first step for the development of an optimal strain through metabolic engineering. Extracellular polysaccharides have several applications in industries, in different product areas such as pharmaceuticals, medicine and foods. Despite their importance, information about fungal polysaccharide synthesis is scarce and an extensive search for new fungal species that can produce novel extracellular polysaccharides is still needed (Mahapatra and Banerjee, 2013). According to Gientka et al (2015), some extracellular polysaccharides of yeasts show antitumor, immunostimulatory and antioxidant activity

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