Genome and Secretome Analysis of Staphylotrichum longicolleum DSM105789 Cultured on Agro-Residual and Chitinous Biomass.

Martin Gand,Arslan Ali,Wilhelm Schäfer,Hartmut Schlüter,Christian Betzel,Hévila Brognaro,Martin Rühl,Bernhard Ellinger,Sophie C Brandt,Carsten Wrenger

doi:10.3390/microorganisms9081581

Abstract

Staphylotrichum longicolleum FW57 (DSM105789) is a prolific chitinolytic fungus isolated from wood, with a chitinase activity of 0.11 ± 0.01 U/mg. We selected this strain for genome sequencing and annotation, and compiled its growth characteristics on four different chitinous substrates as well as two agro-industrial waste products. We found that the enzymatic mixture secreted by FW57 was not only able to digest pre-treated sugarcane bagasse, but also untreated sugarcane bagasse and maize leaves. The efficiency was comparable to a commercial enzymatic cocktail, highlighting the potential of the S. longicolleum enzyme mixture as an alternative pretreatment method. To further characterize the enzymes, which efficiently digested polymers such as cellulose, hemicellulose, pectin, starch, and lignin, we performed in-depth mass spectrometry-based secretome analysis using tryptic peptides from in-gel and in-solution digestions. Depending on the growth conditions, we were able to detect from 442 to 1092 proteins, which were annotated to identify from 134 to 224 putative carbohydrate-active enzymes (CAZymes) in five different families: glycoside hydrolases, auxiliary activities, carbohydrate esterases, polysaccharide lyases, glycosyl transferases, and proteins containing a carbohydrate-binding module, as well as combinations thereof. The FW57 enzyme mixture could be used to replace commercial enzyme cocktails for the digestion of agro-residual substrates.

Highlights

The sustainable valorization of non-edible lignocellulosic biomass facilitates the production of fuels, chemicals, and other carbon-based materials while avoiding competition with food and feed crops [1,2]
To investigate mycelial growth and possible color formation, fungal growth was assessed on potato dextrose agar (PDA), yeast extract peptone dextrose (YPD) [46], complete medium (CM) [47], malt extract agar (MEA) [48], starch casein agar (SCA) [49] and Mandels’ salt medium (MS) [50], each with 2% agar, for 15 days (Figure 1)
We evaluated the growth of S. longicolleum FW57 on six different media, resulting in the formation of pale white to slightly yellow mycelia (Figure 1)

Summary

Introduction

The sustainable valorization of non-edible lignocellulosic biomass facilitates the production of fuels, chemicals, and other carbon-based materials while avoiding competition with food and feed crops [1,2]. Abundant biomass can be obtained from forestry and agricultural waste, such as sugarcane in tropical areas and maize in sub-tropical and temperate 4.0/). Microorganisms 2021, 9, 1581 regions [3,4,5]. Lignocellulosic biomass is heterogeneous in structure and composition, depending on the plant species [7,8,9]. This can impede the enzymatic hydrolysis of biomass [10,11]

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Discussion

Conclusion