PROIMI   05436
PLANTA PILOTO DE PROCESOS INDUSTRIALES MICROBIOLOGICOS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Hydrolytic activity of microbial lipase aggregates induced by heat treatment
Autor/es:
ABDULHAMID, MARÍA BELÉN; COSTAS, LUCIANA; BAIGORI, MARIO DOMINGO; PERA, LICIA MARÍA
Lugar:
Rosario
Reunión:
Congreso; IX Congreso de Microbiología General (SAMIGE); 2013
Institución organizadora:
SAMIGE
Resumen:
Lipases (EC 3.1.1.3) are enzymes characterized by the ability to
catalyze the hydrolysis of triglycerides at the interface between the insoluble
substrate and water. Currently, lipases are a popular
choice as a biocatalyst because they can be applied to chemo-, regio- and
enantioselective hydrolyses and also in the syntheses of a broad range of
compounds. These enzymes are considered to have great potential in numerous
industrial processes, such as the synthesis of food ingredients, their use as
additives to detergents and to obtain enantiopure drugs and other refined products.
In addition, enzyme aggregates have emerged as an interesting biocatalyst
design for immobilization. Generally, they can be produced by different protein
precipitation techniques such as the addition of a salt or an organic solvent. In
this work, the effect of lipase aggregation induced by heat treatment on its
hydrolytic activity was evaluated.
Sixty-four
spore-forming microorganisms isolated from different oil contaminated soil
samples were used. The most promising microorganisms were molecularly
identified by using 16S partial rDNA sequencing. The
extracellular lipase production was carried out by submerged fermentation in
the Luria-Bertani (LB) medium. Hydrolytic activity of either supernatant or
dried sample was measured using p-NPP (p-nitrophenyl palmitate; C16)
as substrate. Cleavage of pNPP was performed at 37 °C in 100 mM phosphate buffer (pH
7.0) containing 0.1% (w/v) Arabic gum and 0.4% (w/v) Triton X-100 .The molar
extinction coefficient of p-nitrophenol (p-NP) under the given assay conditions
was 0.0103 μM−1cm−1. Dried supernatant was obtained by using a
speed vacuum system (Savant Instruments, Inc) for 3 h at 45 ˚C. One unit of
enzyme activity was defined as the amount of biocatalyst that released 1 µmol
of p-NP per min.
In general, it was found that the lipase aggregates induced by heat
treatment showed higher hydrolytic activity than that the corresponding liquid
supernatant. As an example, the hydrolytic activity of heat treated lipases
from Brevibacillus brevis 47M, B. agri 49M, B. agri 52M and B. agri
E12 was increased by 24.6, 454.8, 314.9 and 10.5 %, respectively.
To conclude, the hydrolytic activity of lipase aggregates from different
spore-forming microorganisms has been presented showing an interesting
biotechnological and industrial relevance.
This work was supported by grants PICT 2011?2158
(FONCyT), CIUNT 26/D409 (UNT) and PIP 297 (CONICET).