Roles of pH and phosphate in rare earth element biosorption with living acidophilic microalgae.

The increasing demand for rare earth elements (REEs) has spurred interest in the development of recovery methods from aqueous waste streams. Acidophilic microalgae have gained attention for REE biosorption as they can withstand high concentrations of transition metals and do not require added organic carbon to grow, potentially allowing simultaneous sorption and self-replication of the sorbent. Here, we assessed the potential of Galdieria sulphuraria for REE biosorption under acidic, nutrient-replete conditions from solutions containing ≤ 15 ppm REEs.

Selective Release of Recombinant Periplasmic Protein From Using Continuous Pulsed Electric Field Treatment.

To date, high-pressure homogenization is the standard method for cell disintegration before the extraction of cytosolic and periplasmic protein from . Its main drawback, however, is low selectivity and a resulting high load of host cell impurities. Pulsed electric field (PEF) treatment may be used for selective permeabilization of the outer membrane.

Monitoring and control of E. coli cell integrity.

Soluble expression of recombinant proteins in E. coli is often done by translocation of the product across the inner membrane (IM) into the periplasm, where it is retained by the outer membrane (OM). While the integrity of the IM is strongly coupled to viability and impurity release, a decrease in OM integrity (corresponding to increased "leakiness") leads to accumulation of product in the extracellular space, strongly impacting the downstream process.

Inhibition of E. coli Host RNA Polymerase Allows Efficient Extracellular Recombinant Protein Production by Enhancing Outer Membrane Leakiness.

With the growing interest in continuous cultivation of Escherichia coli, secretion of product to the medium is not only a benefit, but a necessity in future bioprocessing. In this study, it is shown that induced decoupling of growth and heterologous gene expression in the E. coli X-press strain (derived from BL21(DE3)) facilitates extracellular recombinant protein production.

Culture medium density as a simple monitoring tool for cell integrity of Escherichia coli.

During the expression of recombinant proteins in the periplasm of Escherichia coli, the integrity of the outer membrane can change, so that product leaks to the medium. Additional stress can induce lysis, the complete disintegration of both inner and outer membrane, leading to release of both product and host cell proteins. Whether leakiness is unwanted or intentional, appropriate monitoring of leakiness and its distinction from lysis is necessary to ensure product quality and process performance.