In industry, enzymes are often immobilized to generate more stable enzyme preparations that are easier to store, handle, and recycle for repetitive use. Traditionally, enzymes are bound to inorganic carrier materials, which requires caseto-case optimization and incurs additional labor and costs. Therefore, with the advent of rational protein design strategies as part of bottom-up synthetic biology approaches, numerous immobilization methods have been developed that enable the one-step production and immobilization of enzymes onto biogenic carrier materials often directly within the production host, which we here refer to as in vivo immobilization. As a result, nano-to micro-meter-sized functionalized biomaterials, or biologically produced enzyme immobilizates, are obtained that can directly be used for synthetic purposes. In this Perspective, we provide an overview over established and recently emerging in vivo enzyme immobilization methods, with special emphasis on their applicability for (industrial) biocatalysis. For each approach, we present fundamental working principles as well as advantages and limitations guiding future research avenues toward sustainable applications in the bioindustry.

Terpenoids constitute one of the largest and most diverse groups within the class of secondary metabolites, comprising over 80,000 compounds. They not only exhibit important functions in plant physiology but also have commercial potential in the biotechnological, pharmaceutical, and agricultural sectors due to their promising properties, including various bioactivities against pathogens, inflammations, and cancer. In this work, we therefore aimed to implement the plant sesquiterpenoid pathway leading to β-caryophyllene in the heterologous host Rhodobacter capsulatus and achieved a maximum production of 139 ± 31 mg L−1 culture. As this sesquiterpene offers various beneficial anti-phytopathogenic activities, we evaluated the bioactivity of β-caryophyllene and its oxygenated derivative β-caryophyllene oxide against different phytopathogenic fungi. Here, both compounds significantly inhibited the growth of Sclerotinia sclerotiorum and Fusarium oxysporum by up to 40%, while growth of Alternaria brassicicola was only slightly affected, and Phoma lingam and Rhizoctonia solani were unaffected. At the same time, the compounds showed a promising low inhibitory profile for a variety of plant growth-promoting bacteria at suitable compound concentrations. Our observations thus give a first indication that β-caryophyllene and β-caryophyllene oxide are promising natural agents, which might be applicable for the management of certain plant pathogenic fungi in agricultural crop production.

Photolabile protecting groups play a significant role in controlling biological functions and cellular processes in living cells and tissues, as light offers high spatiotemporal control, is non‐invasive as well as easily tuneable. In the recent past, photo‐responsive inducer molecules such as 6‐nitropiperonyl‐caged IPTG (NP‐cIPTG) have been used as optochemical tools for Lac repressor‐controlled microbial expression systems. To further expand the applicability of the versatile optochemical on‐switch, we have investigated whether the modulation of cIPTG water solubility can improve the light responsiveness of appropriate expression systems in bacteria. To this end, we developed two new cIPTG derivatives with different hydrophobicity and demonstrated both an easy applicability for the light‐mediated control of gene expression and a simple transferability of this optochemical toolbox to the biotechnologically relevant bacteria Pseudomonas putida and Bacillus subtilis. Notably, the more water‐soluble cIPTG derivative proved to be particularly suitable for light‐mediated gene expression in these alternative expression hosts.