Lipase of Aspergillus niger NCIM 1207: A Potential Biocatalyst for Synthesis of Isoamyl Acetate

Abstract

Commercial lipase preparations and mycelium bound lipase from Aspergillus niger NCIM 1207 were used for esterification of acetic acid with isoamyl alcohol to obtain isoamyl acetate. The esterification reaction was carried out at 30°C in n-hexane with shaking at 120 rpm. Initial reaction rates, conversion efficiency and isoamyl acetate concentration obtained using Novozyme 435 were the highest. Mycelium bound lipase of A. niger NCIM 1207 produced maximal isoamyl acetate formation at an alcohol/acid ratio of 1.6. Acetic acid at higher concentrations than required for the critical alcohol/acid ratio lower than 1.3 and higher than 1.6 resulted in decreased yields of isoamyl acetate probably owing to lowering of microaqueous environmental pH around the enzyme leading to inhibition of enzyme activity. Mycelium bound A. niger lipase produced 80 g/l of isoamyl acetate within 96 h even though extremely less amount of enzyme activity was used for esterification. The presence of sodium sulphate during esterification reaction at higher substrate concentration resulted in increased conversion efficiency when we used mycelium bound enzyme preparations of A. niger NCIM 1207. This could be due to removal of excess water released during esterification reaction by sodium sulphate. High ester concentration (286.5 g/l) and conversion (73.5%) were obtained within 24 h using Novozyme 435 under these conditions.

Síntese enzimática do caprilato de isopentila utilizando óleo fúsel como matéria-prima

“…3 Possíveis alternativas para o aproveitamento deste subproduto incluem a produção de alcoóis superiores por destilação fracionada, 4 e síntese de ésteres por via química ou biotecnológica. [5][6][7] Ésteres são componentes importantes de aromas naturais e contribuem na formação e acentuação dos aromas em diversos alimentos. [8][9][10][11] Com a demanda crescente de produtos naturais, a indústria de alimentos está interessada no uso da rota biotecnológica para produção de ésteres aromatizantes.…”

“…[5][6][7] Ésteres são componentes importantes de aromas naturais e contribuem na formação e acentuação dos aromas em diversos alimentos.…”

Isoamylacetate production by entrapped and covalently bound Candida rugosa and porcine pancreatic lipases

“…IAAc, as a natural flavour, can be extracted from plants, but this practise is rare and too expensive for commercial use (Güvenç, Kapucu, & Mehmetoglu, 2002;Mhetras, Patil, & Gokhale, 2010). Although it can be synthesized by chemical catalysis cheaply, this would not be considered natural (Güvenç et al, 2002;Mhetras et al, 2010) and it also results in by-products. Hence, IAAc production through enzymatic synthesis may be an attractive/alternative route to traditional chemical synthetic methods (Mhetras et al, 2010).…”

“…Although it can be synthesized by chemical catalysis cheaply, this would not be considered natural (Güvenç et al, 2002;Mhetras et al, 2010) and it also results in by-products. Hence, IAAc production through enzymatic synthesis may be an attractive/alternative route to traditional chemical synthetic methods (Mhetras et al, 2010). This is due to the selectivity of enzymes, milder operation conditions, degree of purity of products and their acceptability in the food industry (Rocha, Gil, & Garcia, 1999).…”

“…Lipase is used widely to hydrolyze ester bonds in aqueous medium in several industries such as pharmacy, food, detergent, cosmetics, oleo-chemicals, fat-processing, leather, textiles and paper (Ozyilmaz, 2009;Ozyilmaz & Gezer, 2010). However, it has been recently used, in view of its synthetic activity in non-aqueous media, to produce several flavour esters, such as IAAc (Feher, Major, Belafi-Bako, & Gubicza, 2009;Güvenç et al, 2002;Mhetras, Patil, & Gokhale, 2010;Ozyilmaz, 2009), butyl acetate (Ozyilmaz & Gezer, 2010;Salah, Ghamghui, Miled, Mejdoub, & Gargouri, 2007), ethyl valerate (Kara-Chaabouni, Ghamgui, Bezzine, Rekik, & Gargouri, 2006;Ozyilmaz & Gezer, 2010), hexyl acetate (Kara-Chaabouni, Ghamgui, Bezzine, Rekik, & Gargouri, 2006), 2-phenylethyl esters (Tan, Yu, Curan, & Liu, 2001) and also non-flavour esters, such as biodisel (Chang, Liao, Lee, & Shieh, 2005;Moreno-Pirajan & Giraldo, 2011;Paula, Urioste, Santos, & de Castro, 2007;Yan, Yan, Liu, Hu, & Wang, 2011), 4-nitrophenylacetate (Ozyilmaz, 2009;Raghuvanshi & Gupta, 2009), 4-nitrophenylpalmitate (Ozyilmaz, 2009) and butyl oleate (Abdul Rahman et al, 2004;Petkar, Lali, Caimi, & Daminati, 2006).…”