Enzyme cocktail with hyperactive lipase through solid-state fermentation by the novel strain Penicillium sp. Y-21

Abstract

Lipase is a kind of industrial enzyme preparation with various catalytic abilities and is widely used in food, energy, medicine and other fields. To increase lipase and enzyme cocktail activity through solid-state fermentation, the novel strain Penicillium sp. Y-21 was obtained through ethyl methanesulfonate (EMS) mutation from the novel strain Y, which was isolated from soils. Solid-state fermentation by strain Y-21 using agricultural byproducts was carried out in tray bioreactors. The optimum culture composition for enzyme cocktail fermentation was soybean meal 20 g, 3% (w/w) glucose, 1% (w/w) peptone, 5% (w/w) lard, 0.04% (w/w) CaCl₂, 0.04% (w/w) FeCl₃, 28 °C for 72 h. The enzyme cocktail produced by strain Y-21 is a kind of multienzyme complex, containing xylanase, glucanase, acidic protease, pectinase, cellulase and lipase, and their enzymatic activities (unit: U g^-1) were 8000, 6000, 8000, 2000, 3000 and 120, respectively. During the fermentation process, the lipase coding genes pel, pha, and p12 were also studied and amplified from the RNA of Penicillium sp. Y-21 by RT-PCR. The results showed that the pel gene played an important role in enzyme production. Afterwards, an enzyme cocktail can be added to chicken feed as an additive, which improves animal growth and feed efficiency.

Figure 1

Diagrams of bench scale tray bioreactor.

Figure 2

Fermentation growth curves of strains in different solid substrates.

Figure 3

Effect of inoculant (A) and substrate moisture (B) on enzyme fermentation.

Figure 4

(A). Effect of additional carbon source and its content on enzyme production. (B). Effect of carbon source concentration on enzyme production by strains. (C). Effect of additional nitrogen source on enzyme production by strains. (D). Effect of nitrogen source concentration on enzyme production by strains.

Figure 5

(A). Effect of metal ions on enzyme production by strains. (B). Effect of Ca²⁺/Fe³⁺ concentration on enzyme production by strains.

Figure 6

Effect of induced oil on lipase production.

Figure 7

SDS-PAGE electrophoresis of enzyme cocktail, purified lipase and protease (1. Marker; 2. Enzyme cocktail; 3. 50% ammonium sulfate; 4. 80% ammonium sulfate; 5. Purified lipase; 6. Purified protease).