Stabilization of Brevibacillus agri 52 lipase activity in organic solvent mixtures and pectin gel encapsulation

COSTAS, LUCIANA; BOSIO, VALERIA ELIZABETH; PANDEY, ASHOK; CASTRO, GUILLERMO RAÚL

Boston-EE.UU

Congreso; 108th American Society for Microbiology; 2008

<!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman"; mso-ansi-language:EN-GB; mso-fareast-language:EN-US;} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 3.0cm 70.85pt 3.0cm; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> Stabilization of Brevibacillus agri 52 lipase activity in organic solvent mixtures and pectin gel encapsulation   Costas L.1, Bosio V.E.1, Pandey A.2 and Castro G.R.1,3 1CINDEFI and University of La Plata (Argentina), 2Regional Research Laboratory (India), 3Tufts University (USA)   Among extracellular hydrolases, lipases produced by Bacillus spp. are powerful tools for biocatalysis. However, enzyme stability in organic solvents remains as serious drawback for its extensive use in Biotechnology. We have demonstrated that the stability of Brevibacillus agri lipase 52 can be extended in non-aqueous media using organic-organic water-soluble mixtures and by encapsulation in pectin gel microspheres. Lipase 52 studied in water-soluble organic solvents was found stable up to 90% diethylenglycol (DEG), glycerol (GLY), and 1,2 propanediol (1,2 PRO) at 37ºC for one hour, and the stability was reduced approximately 20% after twelve hours incubation. However in 40% dimethylsulfoxide (DMSO) the lipase activity was limited to only one hour, and total enzyme inhibition was detected at 20% dimethylformamide (DMF) concentration. Also, lipase 52 precipitates in presence of 50% acetone or ethanol/water mixtures. On the contrary, when DEG (25 to 40%) is added to 30% DMF-water mixtures the lipase activity was higher than 80% and stable for 12 hours. In addition, 20% GLY, or DEG, or 1,2 PRO were able to avoid lipase precipitation in 50% acetone or ethanol - water mixtures, keeping the enzyme activity higher than 70% for one hour at 37ºC. In water immiscible systems the stability of lipase in n-hexane, n-tetradecane and n-heptane resembles the water activity. Encapsulation lipase 52 in pectin gel microspheres increases dramatically the enzyme activity and also the enzyme half-life. The encapsulated lipase 52 have 1.5 to 4.5 times more activity in 70% DEG, DMF, DMSO, Gly, or 1,2 PRO at 37ºC for one hour incubation, and the activity remains between 0.9 to 3.5 times in the same systems for 12 hours compared to aqueous systems. In conclusion, stabilizing hydroxylic solvents and biocompatible pectin encapsulation will provide powerful tools for the use of lipase 52 in long-term bioconversions. Key words: non-aqueous biocatalysis, lipases, enzyme stability, solvent mixtures, pectin gels, gel microspheres, enzyme encapsulation