Optimization of surfactants formulations to stabilise proteases and amylases

The stability of amylase and protease with linear alkylbenzene sulphonate, ethoxylated fatty alcohol, alkylpolyglucoside, and silica microparticles was analysed. Protease showed first order deactivation finding the highest stability (deactivation energy 62.9 Kcal/mol) with linear alkylbenzene sulfonate/ethoxylated fatty alcohol/silica microparticles (10/10/1.5% w/w). Other surfactant formulations with ethoxylated fatty alcohol (20% w/w), alkylbenzene sulfonate/ethoxylated fatty alcohol (10/10% w/w) or linear alkylbenzene sulfonate/ethoxylated fatty alcohol/alkylpolyglucoside (10/5/5% w/w) also stabilised the protease. Linear alkylbenzene sulfonate deactivated the amylase. Linear alkylbenzene sulfonate/ethoxylated fatty alcohol/ alkylpolyglucoside (10/5/5% w/w) and linear alkylbenzene sulfonate/ethoxylated fatty alcohol/silica microparticles (10/10/1.5% w/w) minimised the amylase destabilisation. These formulations also showed high detergency. Alkylbenzene sulfonate promoted protein unfolding and reduced the enzymatic activity, and the non-ionic surfactants stabilised the enzymes, possibly because they interact harmlessly with the enzymes and avoid interaction with the anionic surfactants at the same binding sites. Optimised surfactant formulations were suggested for detergent formulation with amylase and protease.