Genetical Surface Display of Silicatein on Yarrowia lipolytica Confers Living and Renewable Biosilica–Yeast Hybrid Materials

Abstract

In this work, a biological engineering-based biosilica–yeast hybrid material was developed. It was obtained by the aggregation of Yarrowia lipolytica through biosilicification catalyzed using genetically displayed silicatein on its cell surface. With orthosilicate or seawater as the substrate, the silicatein-displayed yeast could aggregate into flocs with a flocculation efficiency of nearly 100%. The resulting floc was found to be a sheetlike biosilica–yeast hybrid material formed by the biosilica-mediated immobilization of yeast cells via cross-linking and embedding, turning the original hydrophilicity of yeast cells into hydrophobicity. In addition, this material was characterized to be porous with an average pore diameter of approximately 10 μm and porosity of over 70%. Because of these properties, this hybrid material could achieve enhanced removal efficiencies for chromium ions and n-hexadecane, which were both above 99%, as compared to the free cells of Y. lipolytica in aqueous environments. Importantly, this hybrid material could be recultivated to generate new batches of yeast cells that maintain parallel properties to the first generation so that the same hybrid material could be reproduced with unchanged highly efficient removal of chromium and n-hexadecane to those of the first generation, demonstrating that this biosilica–yeast hybrid material was living and renewable. This work presented a novel way of harnessing silicatein and Y. lipolytica to achieve biological synthesis of a living inorganic–organic hybrid material that has potential to be applied in water treatment.

Yarrowia lipolytica Strains and Their Biotechnological Applications: How Natural Biodiversity and Metabolic Engineering Could Contribute to Cell Factories Improvement

“…Surface display of silicatein on the surface of GM Y. lipolytica cells has been used by a research team of Ocean University of China (Qindao) to aggregate armed yeasts into flocs, a sheet-like biosilica-yeast hybrid material, for bioremediation applications [ 105 ]. At last, an ambitious and complex engineering work, directed by Huazhong University of Science and Technology (Wuhan, China), led to the design of Euk.cement, an autocementation kit project based on live GM Y. lipolytica cells.…”

Engineered Living Materials: Taxonomies and Emerging Trends

“…The most common bottom-up tactics for growing functional living materials include (i) biofilm formation via secretion of designer extracellular proteins, polysaccharides, enzymes, and other molecules [1]; (ii) surface display and modification of patterned structural proteins [4] or enzymes [5] which can serve as 2D scaffolds for ordering at higher length scales; and (iii) biomineralization of silica or carbonate minerals that can occur on, near, or beyond the cell surface [6] (Figure 3). 2D and 3D living biofilms have been produced by secretion of modified extracellular polymers [1,7], primarily by integrating and manipulating expression of the functional amyloid CsgA (to produce Curli fibers and modifications thereof) and TasA [8,9].…”

Bottom-up approaches to engineered living materials: Challenges and future directions

“…This strategy is used by eukaryotic sponges that use silicateins to catalyze biosilica synthesis from ortho-silicate. 76 When displayed on the surface of yeasts, 94 silicateins caused cells to aggregate by producing a yeast-biosilica hybrid material. The authors showed that this hybrid material could be reinoculated into fresh medium to generate new cultures of yeast cells with properties similar to those of their progenitors, indicating that biosilica does not prevent cell proliferation.…”