Characterization of sol‐gel entrapped chlorophyllase

Abstract

Immobilization of membrane proteins remains a challenge compared to soluble proteins. The membrane protein-chlorophyllase was successful entrapped in tetramethoxysilane (TMOS)-based sol-gel in the presence of lipid. Activity was examined against mixing rate, incubation temperature, time, substrate, acetone, and canola oil concentration. The external mass transfer of chlorophyll is not the rate-limiting step at higher mixing rates. Stability against temperature and acetone as denaturant was enhanced. In spite of the fact that an initial reaction lag phase was observed, 20% more chlorophyll was hydrolyzed, compared to reaction with free enzyme by the end of a 12 h assay. The initial lower activity demonstrated by entrapped chlorophyllase is likely due to the diffusion resistance of chlorophyll into and within the entrapment matrix. This hypothesis was substantiated by a low diffusion coefficient on the order of 10(-14) m(2)/s obtained for chlorophyll in nanoporous sol-gel particles. Pore size distribution of nanoporous wet TMOS-based sol-gel with or without protein was determined by thermoporometry. The change in pore morphology upon doping with chlorophyllase suggests that protein acts as a template during the sol-gel process.

Physiological Characterization and Comparative Transcriptome Analysis of a Slow-Growing Reduced-Thylakoid Mutant of Chinese Cabbage (Brassica campestris ssp. pekinensis)

“…According to KEGG pathway analysis, one DEG ( Bra025756 ) was involved in the porphyrin and chlorophyll metabolism pathway. Bra025756 encodes chlorophyllase, which plays a critical role in chlorophyll degeneration and is crucial for plant development (Hornero-Méndez and Mínguez-Mosquera, 2002 ; Okazawa et al, 2006 ; Yi et al, 2006 ). Chlorophyllase catalyzes the reaction from chlorophyll to chlorophyllide (Fang et al, 1998 ; Hörtensteiner, 1999 ; Tsuchiya et al, 1999 ).…”

Nanotube-supported bioproduction of 4-hydroxy-2-butanone via in situ cofactor regeneration

“…Nevertheless, many industrial bioconversions often involve more than one enzyme, such as in situ cofactor regeneration system, thus studies on multienzyme immobilization are important for understanding these systems (Ei-Zahab et al 2008;Yang et al 2010). In addition to circumventing common problems associated with single enzyme immobilization-enzyme leaching (Kim et al 2006a), strong diffusion resistance (Yi et al 2006), and loss of enzyme 3D structure (Klibanov 1983), other factors such as ratios between enzymes and overall optimal reaction conditions need to be examined in multi-enzymatic immobilization.…”

Internally Self-Assembled Thermoreversible Gelling Emulsions: ISAsomes in Methylcellulose, κ-Carrageenan, and Mixed Hydrogels

“…Formulation, characterization, and specific performance of various gel and hydrogel systems are very important topics of investigation in various fields of research. In this sense, gels can be used as stabilizers of various systems, − slow down dynamics of the systems, , can facilitate sustained or controlled release of various functional molecules, − lead to some other specifically desired properties of the systems, − or be simply used to yield the final product solid-like and in this way facilitate its handling. − In this way, such gels are of special importance in the field of pharmaceutical, cosmetics, and food applications. Our interest lies in the polysaccharides methylcellulose (MC; E461) and κ-carrageenan (KC; E407) that are well-known additives used for gelation in various nutrition and other products.…”