The plant cell wall is the most abundant carbon reservoir in nature and is a renewable source of biofuels. To break down this biomass and convert it into fermentable sugars, a set of multiple enzymes is needed. Here, we characterize the enzymatic repertoire necessary for the degradation of sugarcane bagasse "in natura" and pre-treated using Aspergillus clavatus as a model. 135 unique peptides were identified by Mass Spectrometry MS/MS. 23 of these proteins belong to classes of enzymes involved in biomass degradation and were differentially expressed on various substrates. Each pretreatment changed the sugarcane bagasse composition, which, in turn, led to the differential expression of A. clavatus holocellulases. The deconstruction of "in natura" bagasse demanded the largest set of enzymes due to the structural complexity of this material. Not only different sources of biomass but also different pretreatments of the same source will determine the enzymes required for the most efficient biomass conversion, avoiding the use of non-essential enzymes and consequent financial expense. Understanding A. clavatus nutritional strategies by proteomic analysis of secretome can improve the technology applied to biomass conversion and by-product synthesis. (C) 2020 Published by Elsevier Ltd.