Biorefineries have been profiled as potential alternatives to increase biomass use at the industrial level. However, more efforts are required to improve the sustainability of these facilities through process improvement and product portfolio increase.
Energy matrix diversification has been categorized as the most reliable approach to guarantee energy security in different world regions 
. Currently, most countries depend highly on non-renewable energy sources (i.e., crude oil, natural gas, coal). Price fluctuations and geopolitical conflicts can affect the power, electricity, building, industry, agriculture, and transport sectors 
. This dependence is not convenient because any change in the global context can affect the economic and environmental goals proposed and discussed by international organizations (e.g., the UN). For instance, the Russian Federation’s invasion of Ukraine has affected the energy transition goals and discourse of different European countries (e.g., Germany) 
. Fossil fuel prices, especially coal, increased for heating and power generation in late 2021 
. This increased demand caused a domino effect in coal-exporting countries (e.g., Colombia), because the increase in coal prices reduced the profit margin of coal-dependent industries (e.g., brick-making industries). Therefore, energy matrix diversification is mandatory to guarantee a reliable, affordable, and efficient service for the world population.
Bioenergy has become one of the most important pillars in energy transition topics, as biomass can reduce greenhouse gas emissions (GHG) and environmental damages caused by the excessive use of fossil fuels 
. Biomass is an alternative for energy production, as this renewable resource can contribute to accomplishing the requirements of the transport sector, especially in the aviation and marine sectors 
. On the other hand, sustainable production and consumption patterns have awakened consumers’ interest in bio-based products instead of synthetic ones. Therefore, biomass has been studied as a potential feedstock for producing biomaterials (e.g., bioplastics, biocomposites), bulk chemicals (organic acids, alcohols), nutraceutical products (e.g., antioxidants), biosurfactants (e.g., rhamnolipids, surfactin), and food additives (e.g., sweeteners and preservatives) 
Second-generation biomass has been profiled as a potential raw material to replace crude oil, as different research efforts have demonstrated the possibility of obtaining the same products with a lower environmental impact (e.g., olefins, paraffin) while avoiding food security issues 
. Most studies involve lignocellulosic biomass fractionation and upgrading by implementing biotechnological, thermochemical, physical, and chemical processes 
. Several reactions with specific activation energies and reaction pathways can occur when disrupting biomass, providing a complex mixture of degradation products as described for the evolution pathways of herbal tea waste when implementing hydrothermal conversion 
. Moreover, different process configurations have been proposed for the integral use of all lignocellulosic biomass fractions 
. Nevertheless, the range of products derived from these processes is restricted, as more complex molecules require specific reaction conditions (i.e., temperature, pressure). Therefore, catalysis plays a key role in biomass conversion, as “new products” with a high yield, selectivity, and conversion are achieved at milder operating conditions 
Catalysis occurs in almost all biomass-processing stages (i.e., pretreatment and conversion) 
. Recent trends have promoted heterogeneous catalysis, considering possible catalyst recovery and re-use. Instead, homogenous catalysis has also been studied for most lignocellulosic biomass-upgrading processes (e.g., acid hydrolysis) 
. Biomass-to-biofuels conversion through catalytic processes has been one of the most studied issues due to the low global implementation of bioenergy in the industrial and transport sectors for heat and power requirements 
. In addition, high-value-added compounds produced via heterogeneous catalysis have been studied for the cosmetic, pharmaceutical, and chemical sectors. Thus, the integral processing of lignocellulosic biomass by implementing catalytic processes can help reach the proposed decarbonization and climate change mitigation goals. Furthermore, lignocellulosic biomass upgrading through catalytic processes avoids a structural and technological shift in the industry and transport sectors 
. Advantages related to the catalytic upgrading of biomass are (i) improvement of different processes’ sustainability by reducing energy requirements, (ii) production of platform molecules as a strong option to diversify the list of bio-based products derived from biomass, and (iii) reduction in waste streams 
. Thus, lignocellulosic biomass conversion involving catalytic processes can contribute to reaching energy transition and fossil fuel independence goals faster.
2. Biorefineries and Catalytic Biomass Upgrading
Lignocellulosic biomass conversion in biorefineries has been analyzed based on the main biomass constituents. These facilities are complex systems where biomass is integrally processed or fractioned to obtain more than one product, including bioenergy, biofuels, chemicals, and high-value-added compounds 
. Biorefineries are designed while considering a comprehensive study of the raw materials and promising technologies 
. These facilities have been proposed as the starting point for developing and implementing a consolidated bioeconomy 
. Thus, biorefineries can help to accomplish the Sustainable Development Goals (SDGs) proposed by the UN.
Biorefineries’ implementation has been slowed, as current technologies upgrade non-renewable resources at the industrial level. Therefore, the transition from crude-oil refineries to biorefineries remains slow compared to the research on biomass upgrading at a lab scale 
. A path towards easier industrial biomass use, leaving aside traditional uses (i.e., combustion), is to upgrade biomass-derived products through catalytic processes to obtain chemicals without requiring an in-depth technological transition. Therefore, catalysis is crucial for (i) shortening distances between academia and industry regarding biomass use, (ii) enhancing biorefinery designs, (iii) creating new biomass conversion pathways, and (iv) increasing processes’ sustainability. Biorefineries comprise thermochemical, biotechnological, chemical, and physical processes through which several compounds can be produced. Thus, catalytic upgrading can be present in all these processes. Indeed, several research efforts have demonstrated the importance of applying catalysis to improve technical indicators (i.e., yields, productivity, and product purity) 
3. Recent Trends Related to Catalytic Processes for Improving Biorefineries’ Designs
Catalytic upgrading of biomass has increased in recent years in order to obtain more bio-based products that can be used in any productive sector. Therefore, different research efforts have been focused on analyzing new ways to implement catalytic processes for biomass upgrading or waste-streams valorization 
. This section refers to some trends related to the catalytic upgrading of bio-based compounds. However, there are more trends worthy of being studied and analyzed. The trends presented are as follows: biocatalysis, CO2
-upgrading, catalysts’ recyclability and use, and biochar as catalysts’ source. The above-mentioned research lines in catalytic processes aim to improve biorefineries’ designs, as more products can be involved in a biorefinery. Moreover, the sustainability of these facilities is upgraded due to the emissions reduction and waste-streams minimization.