Surface-Displayed Thermostable Candida rugosa Lipase 1 for Docosahexaenoic Acid Enrichment

Surface-displayed phenolic acid decarboxylase for increased vinylphenolic pyranoanthocyanins in blueberry wine

During the fruit wine production, phenolic acid decarboxylase (PAD) converts free hydroxycinnamic acid into 4-vinyl derivatives that can then react spontaneously with anthocyanins, generating more stable pyranoanthocyanins that are responsible for the color stability of fruit wine. Nevertheless, the low PAD activity in yeast under the winemaking conditions has largely limited the generation of 4-vinyl derivatives. To bridge this gap, we expressed PAD from Bacillus amyloliquefaciens in Pichia pastoris and surface-displayed it on Saccharomyces cerevisiae. As a result, S. cerevisiae surface-displayed PAD (SDPAD) exhibited an enhanced thermal stability and tolerance to acidic conditions. Fermentation experiments showed that SDPAD can significantly increase the content of vinylphenolic pyranoanthocyanins and thus maintain the color stability of blueberry wine. Our study demonstrated the feasibility of surface display technology for color stability enhancement during the production of blueberry wine, providing a new and effective solution to increase the content of vinylphenolic pyranoanthocyanins in the fruit-based wines.

Characterization of yeast cell surface displayed Lentinula edodes xylanase and its effects on the hydrolysis of wheat

The current study displayed a xylanase from Lentinula edodes on the surface of Pichia pastoris (sdLeXyn) and investigated its properties and effects on the wheat hydrolysis. Fluorescence microscope results showed that sdLeXyn was successfully anchored and displayed on the surface of P. pastoris X-33 cells. The highest activity of sdLeXyn was obtained at pH 3.0 and 50 °C. The sdLeXyn exhibited anti-high temperature property and showed broad temperature adaptability (>55% of the highest activity at 20-80 °C). The sdLeXyn was very stable at room temperature and could remain functionally stable at 50 °C for 3 h. The K_m value was greater in sdLeXyn than that in free recombinant L. edodes xylanase. The sdLeXyn exhibited well resistance to Mn²⁺, Zn²⁺, Ca²⁺, Na⁺, Cu²⁺, Mg²⁺, K⁺, Ni²⁺ (1 mM and 5 mM) except Cu²⁺, which reduced the sdLeXyn activity by 54.5% at 5 mM dosage. The activity of sdLeXyn was increased by 42.6% by 5 mM Mn²⁺, 5 mM DTT, Trition X-100, and Tween 20 did not affect the activity of sdLeXyn, but SDS and EDTA slightly reduced it by 12.8% and 14.6%, respectively. The sdLeXyn could resist the degradation of pepsin, efficiently hydrolyzed wheat and reduced the viscosity of wheat hydrolysate. Current data indicate that the sdLeXyn has a potential as a feed additive to improve the utilization of wheat in poultry production.

Codisplay of Rhizopus oryzae and Candida rugosa Lipases for Biodiesel Production

In this study, we overcame the limitations of single-enzyme system catalysis by codisplaying Candida rugosa lipase 1 (CRL1) and Rhizopus oryzae lipase (ROL) on the cell surfaces of the whole-cell catalyst Pichia pastoris to produce biodiesel from tallow seed oil. We screened double antibiotic-resistant strains on tributyrin plates, performed second electroporation based on single-displayed ROL on GS115/KpRS recombinants and single-displayed CRL1 on GS115/ZCS recombinants and obtained an ROL/CRL1 codisplay on P. pastoris GS115 surfaces. The maximum activity of the codisplaying GS115/pRCS recombinant was 470.59 U/g dried cells, which was 3.9-fold and 1.3-fold higher than that of single-displayed ROL and CRL1, respectively. When self-immobilized lipases were used as whole-cell catalysts, the rate of methyl ester production from GS115/pRCS harboring ROL and CRL1 was 1.4-fold higher than that obtained with single-displayed ROL. Therefore, biodiesel catalysis by synergetic codisplayed enzymes is an alternative biodiesel production strategy.

One Pot Use of Combilipases for Full Modification of Oils and Fats: Multifunctional and Heterogeneous Substrates

Lipases are among the most utilized enzymes in biocatalysis. In many instances, the main reason for their use is their high specificity or selectivity. However, when full modification of a multifunctional and heterogeneous substrate is pursued, enzyme selectivity and specificity become a problem. This is the case of hydrolysis of oils and fats to produce free fatty acids or their alcoholysis to produce biodiesel, which can be considered cascade reactions. In these cases, to the original heterogeneity of the substrate, the presence of intermediate products, such as diglycerides or monoglycerides, can be an additional drawback. Using these heterogeneous substrates, enzyme specificity can promote that some substrates (initial substrates or intermediate products) may not be recognized as such (in the worst case scenario they may be acting as inhibitors) by the enzyme, causing yields and reaction rates to drop. To solve this situation, a mixture of lipases with different specificity, selectivity and differently affected by the reaction conditions can offer much better results than the use of a single lipase exhibiting a very high initial activity or even the best global reaction course. This mixture of lipases from different sources has been called “combilipases” and is becoming increasingly popular. They include the use of liquid lipase formulations or immobilized lipases. In some instances, the lipases have been coimmobilized. Some discussion is offered regarding the problems that this coimmobilization may give rise to, and some strategies to solve some of these problems are proposed. The use of combilipases in the future may be extended to other processes and enzymes.