Stabilizing bromelain for therapeutic applications by adsorption immobilization on spores of probiotic Bacillus

Abstract Bromelain, a protease from pineapple plant can be applied as oral drug for the treatment of inflammation and certain diseases. Unlike most conventional supports, immobilization on edible support will make the enzyme suitable for therapeutic use. In this study, spores of probiotic Bacillus sp was used for the adsorption of bromelain. Effect of pH, temperature and enzyme concentration on bromelain immobilization was studied, followed by characterization of the enzymes. Maximum bromelain coupling (%) (50.607 ± 4.194) was obtained when immobilization was carried out at pH 6.0, 24 °C for 150 min. The immobilized enzyme showed optimum activity at pH 8 and 80 °C, while the free enzyme had 6 and 60 °C as its optimum pH and temperature, respectively. Bromelain Vmax increased after immobilization while Km decreased. Activation energy, Ea was 26.513 kJ/mol and 20.942 kJ/mol for the free and immobilized enzymes, respectively. The immobilized bromelain also showed significantly greater storage and thermal stability than the free bromelain. At 80 °C, the free bromelain lost all its activity after 50 min while the immobilized enzyme lost only 46.89% activity. Bromelain was successfully immobilized on Bacillus spores with improved catalytic and non-catalytic properties and this holds great potential for its growing therapeutic applications.