Chain-lenght selectivity of an extracellular lípase activity from Aspergillus níger MYA 135

ROMERO CINTIA M.; PERA L; BAIGORÍ M

Cordoba

Congreso; SAIB. 44 Annual Meeting. Argentina. (Argentina). XLIV Reunion Annual. Sociedad Argentina de Investigación en Bioquímica y Biología Molecular.; 2008

Chain-Length selectivity of an extracellular lipase activity from Aspergillus niger MYA 135. The lipases (EC 3.1.1.3.) have atracted the great interest of chemical and pharmaceuticl industries due to their useful in both hydrolysis and synthesis reactions. Chain-length specificity has been related to structural features of lipases, but up to now, no lipase has been described as strictly specific for a given chain-length. The objetive of this work was to determine the selectivity of an extracellular lipase towards different chain-lengy substrates during hydrolysis, esterification and transesterifications reactions. All test were carried aut with 0.01 g of freeze-dried supernatant. Transesterifications and esterifications were permormed in n-hexane using p-nitrophenyl alkyl esters (C10,12,16,18) and acids (Caprilic, caproic, linolei, palmitic), respectively. Alcohols with chain length from C1 to C7 were also used as substrates. Hydrolysis was determined using 1- and 2-naphtyl acetate, myristate, palmitate, laurate and estearate. The results wre expressed using the specificity constant 1 /a described by Rangheard. In hydrolysis reaction the lipase presents a clear preference for 1-nafçphtyl laurate .(1/a = 0.78). Concerning esterification, the maximum rate (1/a= 1) was reached in the presence oflinoleic acid and butanol. For transesterifications. there were preference for C12 and C10 using methanol.