Immobilization Techniques on Bioprocesses: Current Applications Regarding Enzymes, Microorganisms, and Essential Oils

The instability of several macromolecules (e.g., enzymes and essential oils) under such factors as pH, temperature, and organic solvents may render their application in industrial and biotechnological processes nonviable. To overcome these drawbacks, some alternatives have been proposed, which includes immobilization. This technique corresponds to the confinement of a compound of interest within/to a support or matrix through different mechanisms (e.g., adsorption, entrapment, and covalent attachment). Although this methodology has been widely explored for innovative and multifaceted applications, it does have some limitations such as additional costs and loss or reduction of activity of the immobilized compound. However, depending on the immobilization technique used, some advantages such as ability to protect compounds, catalyst reuse, and easier product separation may outweigh these disadvantages. In this regard, new techniques and the immobilization varied materials of interest are in development, and contribute to a substantial growth in the number of publications in this field of study. Due to the large increase of research, several new articles are published daily; therefore, reviews that summarize this field are important. This review focuses on the use of immobilization techniques and their advantages in bioprocesses based on three main groups and related applications: (1) immobilized enzymes for biodiesel, flavoring agent, and antimicrobial compound production; (2) immobilized microorganisms for ingredient production, wastewater treatment, and probiotic protection; (3) immobilized essential oils for food preservation and as ingredients in pharmaceuticals and cosmetics. Furthermore, conclusions and future perspectives are discussed, aiming at improvement of existing processes and the release of new technologies for industrial use with less costs.