# Lacase in Biorefinery of Lignocellulosic Biomass
## 7 Challenges and Future Directions  
Despite the many advantages of laccase-based biorefinery approaches and other applications, there are several challenges that need to be addressed. The main challenges include the high the cost, availability and slow reaction of laccase enzymes, which can limit the scalability of the process. Laccase low activity and stability under industrial conditions are a big limit to its commercialization. Laccase is highly sensitive to temperature, pH, and inhibitors; hence, robust laccase production is crucial for its commercialization [90]. Its production is expensive and requires specialized equipment and skilled personnel. The high cost of laccase production often limits its use in lignocellulosic biomass conversion [91]. However, immobilization of laccases has been explored to improve their effectiveness and reduce the cost to some extent [92]. Laccase has a narrow substrate specificity, which limits its ability to degrade a wide range of lignocellulosic biomasses. This can result in the incomplete degradation of lignin and limited access to cellulose and hemicellulose. Improving the substrate specificity of laccase can enhance its efficiency and effectiveness in lignocellulosic biomass conversion [93]. Lignin-derived phenols, such as vanillin, syringaldehyde, and coniferly alcohol, lignin-derived lignans, such as pinoresinol and lariciresinol, lignin-derived flavonoids include compounds such as kaempfer and quercetin, lignin-derived stillenes such as resveratrol and piceatannol, lignin-derived cinnamic acids such as p-coumaric acid and ferulic acid are known to inhibit lactose and negatively affect the biorefinery process [94]. However, with continued research and development, lactose-based biological processes are becoming the key technology for the production of bio-based products from lignocellulosic biomass. Laccase-based biological pretreatment can be integrated with other pretreatment methods, such as steam explosion, microwave-assisted pretreatment and acid hydrolysis, to enhance its efficiency and effectiveness [95]. However, the integration of different pretreatment methods requires careful optimization to avoid negative interactions and maximize the benefits of each method [96]. Several future directions can be explored to enhance its efficiency and effectiveness. The engineering of lactose can improve its activity, stability, and substrate specificity. This can be achieved through genetic modification or protein engineering to enhance its properties and make it more suitable for industrial applications [97]. Recent studies have used various techniques, such as directed evolution, rational design, and protein engineering, to develop novel lactose variants with improved properties. In addition, the identification of new lactose enzymes from different sources, such as bacteria and fungi, can expand the diversity of lactose enzymes and provide new opportunities for biorefinery [98]. The use of statistical experimental designs, such as response surface methodology, can facilitate the optimization process even for engineered microbes [99]. Understanding the mechanisms of lignin degradation by laccase is necessary, which involves the cleavage of various types of bonds and the release of different types of products. Laccase plays a critical role in the oxidation of lignin, which can lead to the depolymerization of lignin and the release of valuable aromatic compounds. Understanding the mechanisms of lignin degradation by laccase can help design more efficient biorefinery processes. Recent studies have used various techniques, such as NMR spectroscopy, mass spectrometry, and computational modeling, to elucidate the mechanisms of lignin degradation by laccase [100]. Scale-up of the laccase-based biorefinery process is crucial for industrial applications. The development of scalable and cost-effective biorefinery processes can promote the utilization of lignocellulosic biomasses as a sustainable feedstock.