Immobilized Horseradish Peroxidase on Enriched Diazo-Activated Silica Gel Harnessed High Biocatalytic Performance at a Steady State in Organic Solvent

Dimethyldichlorosilane (DMDCS), an efficient silane coupling reagent appearing between the −OH groups of silica gel (SG) and picric acid, instantaneously produces a derivative enriched with nitro groups. The nitro group acting as an end-cap terminates the reaction and subsequently was converted into diazo to couple tyrosine’s phenol ring via its O-carbon, the inert center to immobilize horseradish peroxidase (HRP) in a multipoint mode. It maintains the status quo of the native enzyme’s protein folding and the entire protein groups’ chemistry. The molecular formula of the synthesized material was verified and appeared as {Si­(OSi)4 (H2O) x } n {−O–Si­(CH3)2–O–C6H2(N+N)3(HRP)}4·yH2O; the parameters were evaluated as x = 0.5, n = 1158, and y = 752. The immobilized biocatalyst’s activity in organic solvents was 1.5 times better than that in an aqueous medium; it worked smoothly, wherein the activity in both solvents stabilized at six months and continued up to nine months at 63 ± 3% compared to the initial.