Chain-length selectivity of an extracellular lipase activity from Aspergillus niger MYA 135

ROMERO CINTIA M.; PERA L; BAIGORÍ M

Villa Carlos Paz- Cordoba

Congreso; SAIB 44th Annual Meeting; 2008

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

The lipases (EC 3.1.1.3) have attracted the great interest of chemical and pharmaceutical industries due to their useful in both hydrolysis and synthesis reactions. Chain-length specificity has been related to structural features of lipases, but no lipase has up to now been described as being strictly specific for a given chain length.The objective of this work was to determine the selectivity of an extracellular lipase towards different chain-length substrates during hydrolysis, esterification and transesterifications reactions. All the tests were carried out with 0.01 g of freeze-dried supernatant. Transesterifications and esterifications were performed in n-hexane using p-nitrophenyl alkyl derivatives (C10, C12, C16, C18) and acids (caprilic, caproic, linoleic, palmitic), respectively. Alcohols with chain length from C1 to C7 were also used as substrates. Hydrolysis was determined using á and â-naphtyl acetate, miristate, palmitate, laurate and estearate. The results were expressed using the specificity constant 1/á described by Rangheard. In hydrolysis reaction the lipase presents a clear preference for á-naphtyl laurate (1/á=0.78). Concerning esterification, the maximum rate (1/á=1) was reached in the presence of linoleic acid and butanol. For transesterification, there was a preference for C12 (1/á=1) and C10 (1/á=0.9) using methanol. This work was supported by grants PIP 6062