The main objective of the Ph.D. research was to develop a biological method for processing pumpkin pomace by cultivating Thermomyces lanuginosus under solid-state fermentation conditions (SSF) to produce lipase and pumpkin pomace with improved quality. In the first part of the research, a rapid spectrophotometric assay was developed to measure the initial reaction rate of ester bond hydrolysis with lipase from T. lanuginosus (TLL), and Hill's kinetic model was proposed to estimate the kinetic parameters of pNP-palmitate hydrolysis. The second part of the research was concerned with the optimization of the conditions of the SSF process, and a mathematical model was developed to predict lipase production. After the validation of the mathematical model, the characterization of lipase was performed. In addition, TLL production was scaled up by performing the SSF process in the tray bioreactor. The produced lipase was used as a biocatalyst in the hydrolysis reaction of different types of oils, which confirmed the broad substrate specificity of the produced TLL. In addition, the high efficiency of the partially purified TLL in the hydrolysis of waste sunflower oil was confirmed. Moreover, the SSF process improved the chemical composition of the substrate and suggested the possibility of using the bioprocessed pomace to produce animal feed. Finally, the feasibility of the lipase and production of the pumpkin pomace with improved quality was confirmed, rounding out the valorization process of lignocellulosic biomass, achieving a "zero waste" approach, and validating the proposed biorefinery concept.