enzyme formulations should stay active and devoid of all possible inactivation processes during transport and long - term storage . the stabilization of enzymatic activity , especially in presence of critical functional components for specialized application , has been a long - standing obstacle when stored over an extended period of time . one such obstacle is the stability of enzyme in presence of weak acids in formulation , which is often desired to efficiently break down biopolymer filtercake embedded in a carbonate matrix , in the open - hole section of a horizontal well , for hydrocarbon production . the invention comprises methods and compositions to enhance the long - term storage stability of an enzyme formulation consisting of an in - situ acid precursor system , where in - situ generated precursors are mainly ester compounds that dissociate by slow hydrolysis to generate organic acid , shifting the ph of the formulation outside the pka of the enzyme protein . the methods and compositions include the addition of high concentrations of metal halide salts , a ph control additive , and a water activity reducing agent . the methods and compositions of the invention provide a high degree of stability for enzyme formulation at long - term storage conditions .