Search

The concept of biocatalytic PET degradation for industrial recycling processes had made a big step when the bacterium Ideonella sakaiensis was discovered to break PET down to its building blocks at ambient temperature. This process involves two enzymes: cleavage of ester bonds in PET by PETase and in MHET, the resulting intermediate, by MHETase. To understand and further improve this unique capability, structural analysis of the involved enzymes was aimed at from early on. We describe a repertoire of methods to this end, including protein expression and purification, crystallization of apo and substrate-bound enzymes, and modeling of PETase complexed with a ligand.

Nowadays, miniaturized digital image sensors are present in various applications ranging from consumer products such as camera phones to scientific and medical instruments. Because of the rapid reduction of structure size in semiconductor technology, small-sized image sensors have become feasible. Manufacturing of miniaturized cameras and the integration of these imagers into imaging microsystems are possible with advanced technologies developed in micro-optics and micromechanics. In this chapter, the general principles of image detectors and the major types of sensors are described. Aspects of process technology, packaging, and optics for miniaturized imagers are addressed. Examples of different applications are discussed for medical endoscopy, scanning microscopy, and volume products such as cellular phones.

Publisher Summary Many organisms require nickel for growth. This chapter discusses the function and properties of three nickel enzymes. Methanogenic bacteria are dependent on nickel for growth. In an earlier study, by using the radioactive isotope 63Nickel, it was shown that about 50% of the nickel taken up by these organisms was incorporated into factor F430. All methanogenic bacteria are able to grow on H2 and CO2 as sole energy sources. These organisms contain two uptake hydrogenases. The name uptake hydrogenase points out that the physiological role of these enzymes is to catalyze the uptake of hydrogen rather than its formation. The synthesis of both hydrogenases is dependent on nickel, which indicates that nickel is an essential component of both enzymes.