Small buds to blooming flowers: organic–inorganic hybrid nanoflowers as immobilization platform and robust system for bio-catalytic production of d-allose

Abstract

D-Allose is a rare monosaccharide and a low-calorie sweetener found in tiny amounts in nature with potential health benefits. Its scarcity in nature and high production cost pose a challenge to industry. The enzymatic route for D-allose production using L-rhamnose isomerase (L-RI_M) is a promising and sustainable approach. The sensitivity of the enzyme to pH and temperature limits its application. In this study, we have developed manganese-based hybrid micro-structures (L-RI_MnNFs) that offer robustness and recyclability to the enzymatic process of D-allose biosynthesis. The hybrid of organic and inorganic microstructure attains flower-like morphology, with each petal in the nanometer dimensions as visualized under electron microscopy. Molecular dynamics (MD) simulations were performed to understand the formation of these flower-like structures. These nanoflowers (NFs) exhibited better kinetic properties and reusability, retaining almost >60% activity even after the 6th cycle of reaction. So far, this study is the first attempt to immobilize L-rhamnose isomerase enzyme onto hybrid nanoflowers (hNFs) and to conduct simulation studies thereof. It provides insights into the improved robustness and durability of L-RI_M after immobilization with a turnover number of 679.9 s⁻¹. These NFs can be developed into biocatalytic platforms for the production of rare sugars.