Targeting to improve the utilization of lignocellulosic residues in the ethanol processing industry, this work aimed to test if the product inhibition of the enzymatic hydrolysis could be relieved by extractive reaction using aqueous two-phase systems (ATPS). The performance of enzymatic hydrolysis in ATPS is not well defined in literature. In this thesis, this extractive reaction was tested in terms of experimental conversion of sugarcane bagasse, simulations through conceptual process design and economic feasibility. A thermodynamic framework was developed in order to predict ATPS formation. The screening of ATPS and partition coefficient of the solutes were performed in a high throughput station. The ATPS were composed by polymer and salt. The enzymes were represented by the enzymatic cocktail Cellic CTec (Novozymes). The development of this platform consisted of two main parts: determination of phase diagrams (binodal curves and tie lines) and quantification of the solutes (sugar and proteins) in both top and bottom phases. The most promising ATPS were experimentally explored for enzymatic hydrolysis of sugarcane bagasse. Process design simulated two scenarios: hydrolysis occurring in the bottom phase and in the top phase. Topics such as the adsorption of phase forming components to the bagasse fibers and the influence of enzyme load on the hydrolysis were explored. The sugarcane bagasse hydrolysis in ATPS was conceptually assessed through the implementation of a model composed by two parts: hydrolysis and ATPS multi-batch separation. The designed case characterized by the ATPS hydrolysis was compared to the base case defined as conventional hydrolysis. Regarding the thermodynamic modelling of ATPS, the application of Flory-Huggins (FH) model to predict phase separation in polymer-salt systems was assessed. The implementation and analysis of FH theory involved the estimation of interchange energy (푤푖푗) and the calculation of phase diagrams. There were no statistical differences in determining the phase diagram in HTP platforms and bench-scale, verifying the reliability of methods and equipment suggested in this work. Moreover, tailored approaches to quantify the solutes were 8 presented, taking into account the limitations of techniques that can be applied with ATPS due to the interference of phase forming components with the analytics. This fast methodology proposes to screen up to six different polymer-salt systems in eight days and supplies the results to understand the influence of sugar and protein concentrations on their partition coefficients. Exploring experimentally the ATPS hydrolysis provided strategies on how to conduct extractive enzymatic hydrolysis in ATPS and how to explore the experimental results in order to design a feasible process. In the conceptual design of extractive enzymatic hydrolysis, one of the major bottlenecks identified was the partitioning of glucose to both phases. The resultant conceptual process design operates as a tool to evaluate ATPS hydrolysis and compare it to conventional one. On the other hand, the thermodynamic model could not quantitatively describe the data. This occurs mainly because of the strong influence of random experimental errors on the estimation of interchange energy, systematic errors when translating the observed data to calculated partition concentrations, and FH not being an exact description of phase separation in salt based ATPS. The high throughput screening methodology indicated ATPS able to partition sugar and enzymes. The selected ATPS presented no significant improvements to perform the enzymatic conversion of sugarcane bagasse compared to the conventional hydrolysis. The main reasons were the influence of phase forming components on the enzymatic activity and the low selectivity of sugars in the ATPS. To disclose the application of ATPS in the ethanol processing industry, the recovery and reuse of the phase forming components are imperative for economic feasibility. Moreover, the developed high throughput platform could be further employed to exhaustively screen systems to design effective ATPS for the partition of sugars and proteins in polymer-salt systems.@en

This thesis presents novel ways of recovering of valuable compounds from food industry side streams. It does so via evaluating two case studies for the valorization of such streams. These types of streams are often referred to as waste and discarded. However, they are rich sources of nutraceuticals (e.g polyphenols), proteins and dietary fiber. Recently the use of these side streams has gained significant interest in the scientific community and different alternatives to recover high value products are being investigated that may contribute to the transition from the current linear economy to a more circular economy.@en

Sesquiterpenes are a versatile group of 15-carbon molecules, traditionally extracted from plants for diverse applications ranging from fuels to fine chemicals and pharmaceuticals. Scarcity of natural resources and emergence of new applications have encouraged the development of sustainable solutions to produce sesquiterpenes. The recent development of engineered microbial strains able to produce and secrete sesquiterpenes reaching fermentation titres in the order of g per L, is a promising alternative to produce diesel-like biofuels from renewable biomass sources, like sugar cane bagasse. The most attractive aspect of sesquiterpene fermentations is that the extracellular product readily forms an oil phase separated from the aqueous fermentation broth in the reactor. The difference of densities between the aqueous broth and the light product phase opens the opportunity of integrating cost-efficient separation techniques (e.g. gravity separation, hydro-cyclones) with the reactor. This scenario could contribute to significantly lowering equipment and utility costs as well as reducing cost of raw materials by allowing for cell recycling. The scale-up of sesquiterpene fermentations has unveiled processing challenges that were not prominently present at laboratory scale. @en