Two alternative cell-surface display systems were developed in Pichia pastoris using the alpha-agglutinin and Flo1p (FS) anchor systems, respectively. Both the anchor cell wall proteins were obtained originally from Saccharomyces cerevisiae. Candida antarctica lipase B (CALB) was displayed functionally on the cell surface of P. pastoris using the anchor proteins alpha-agglutinin and FS. The activity of CALB displayed on P. pastoris was tenfold higher than that of S. cerevisiae. The hydrolytic and synthetic activities of CALB fused with alpha-agglutinin and FS anchored on P. pastoris were investigated. The hydrolytic activities of both lipases displayed on yeast cells surface were more than 200 U/g dry cell after 120 h of culture (200 and 270 U/g dry cell, respectively). However, the synthetic activity of CALB fused with alpha-agglutinin on P. pastoris was threefold higher than that of the FS fusion protein when applied to the synthesis of ethyl caproate. Similarly, the CALB displayed on P. pastoris using alpha-agglutinin had a higher catalytic efficiency with respect to the synthesis of other short-chain flavor esters than that displayed using the FS anchor. Interestingly, for some short-chain esters, the synthetic activity of displaying CALB fused with alpha-agglutinin on P. pastoris was even higher than that of the commercial CALB Novozyme 435.

A Pichia pastoris cell-surface display system was constructed using the Sed1 anchor system that has been developed in Saccharomyces cerevisiae. Candida antarctica lipase B (CALB) was used as the model protein and was fused to an anchor that consisted of 338 amino acids of Sed1. The resulting fusion protein CALBSed1 was expressed under the control of the alcohol oxidase 1 promoter (pAOX1). Immunofluorescence microscopy of immunolabeled Pichia pastoris revealed that CALB was displayed on the cell surface. Western blot analysis showed that the fusion protein CALBSed1 was attached covalently to the cell wall and was highly glycosylated. The hydrolytic activity of the displayed CALB was more than 220 U/g dry cells after 120 h of culture. The displayed protein also exhibited a higher degree of thermostability than free CALB.

Despite stringent power consumption requirements in many applications, over years organic light‐emitting diode (OLED) displays still suffer unsatisfactory energy efficiency due to poor light extraction. Approaches have been reported for OLED light out‐coupling, but they in general are not applicable for OLED displays due to difficulties in display image quality and fabrication complexity and compatibility. Thus to date, an effective and feasible light extraction technique that can boost efficiencies and yet keep image quality is still lacking and remains a great challenge. Here, a highly effective and scalable extraction‐enhancing OLED display pixel structure is proposed based on embedding the OLED inside a three‐dimensional reflective concave structure covered with a patterned high‐index filler. It can couple as much internal emission as possible into the filler region and then redirect otherwise confined light for out‐coupling. Comprehensive multi‐scale optical simulation validates that ultimately high light extraction efficiency approaching ≈80% and excellent viewing characteristics are simultaneously achievable with optimized structures using highly transparent top electrodes. This scheme is scalable and wavelength insensitive, and generally applicable to all red, green, and blue pixels in high‐resolution full‐color displays. Results of this work are believed to shed light on the development of future generations of advanced OLED displays.