5 Bioconversion and downstream processing in the context of biorefinery: Principles and process examples

Abstract: Algae (both micro and macro) have gained huge attention in the recent past for their high commercial value products. They are the source of various biomolecules of commercial applications ranging from nutraceuticals to fuels. Phycobiliproteins are one such high value low volume compounds which are mainly obtained from micro and macro algae. In order to tap the bioresource, a significant amount of work has been carried out for large scale production of algal biomass. However, work on downstream processing aspects of phycobiliproteins (PBPs) from algae is scarce, especially in case of macroalgae. There are several difficulties in cell wall disruption of both micro and macro algae because of their cell wall structure and compositions. At the same time, there are several challenges in the purification of phycobiliproteins. The current review article focuses on the recent developments in downstream processing of phycobiliproteins (mainly phycocyanins and phycoerythrins) from micro and macroalgae. The current status, the recent advancements and potential technologies (that are under development) are summarised in this review article besides providing future directions for the present research area.

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A. Fiechter (Editor), Downstream Processing. 202 S., 72 Abb., 18 Tab. Berlin 1983. Akademie-Verlag. M 88,00

Zeitschrift für allgemeine Mikrobiologie ◽

10.1002/jobm.3630241005 ◽

1984 ◽

Vol 24 (10) ◽

pp. 690-690

Author(s):

G. Barth

Keyword(s):

Downstream Processing

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Two-Step Solvent Extraction of Radioactive Elements and Rare Earths from Estonian Phosphorite Ore Using Nitrated Aliquat 336 and Bis(2-ethylhexyl) Phosphate

Minerals ◽

10.3390/min11040388 ◽

2021 ◽

Vol 11 (4) ◽

pp. 388

Author(s):

Silvester Jürjo ◽

Liis Siinor ◽

Carolin Siimenson ◽

Päärn Paiste ◽

Enn Lust

Keyword(s):

Rare Earth ◽

Solvent Extraction ◽

Rare Earth Elements ◽

Toxic Elements ◽

Downstream Processing ◽

Liquid Extraction ◽

Aliquat 336 ◽

Radioactive Elements ◽

Improved Method ◽

Ph Values

Estonian phosphorite ore contains trace amounts of rare earth elements (REEs), many other d-metals, and some radioactive elements. Rare earth elements, Mo, V, etc. might be economically exploitable, while some radioactive and toxic elements should be removed before any other downstream processing for environmental and nutritional safety reasons. All untreated hazardous elements remain in landfilled waste in much higher concentration than they occur naturally. To resolve this problem U, Th, and Tl were removed from phosphorite ore at first using liquid extraction. In the next step, REE were isolated from raffinate. Nitrated Aliquat 336 (A336[NO3]) and Bis(2-ethylhexyl) Phosphate (D2EHPA) were used in liquid extraction for comparison. An improved method for exclusive separation of radioactive elements and REEs from phosphorite ore in 2-steps has been developed, exploiting liquid extraction at different pH values.

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Controlling Unconventional Secretion for Production of Heterologous Proteins in Ustilago maydis through Transcriptional Regulation and Chemical Inhibition of the Kinase Don3

Journal of Fungi ◽

10.3390/jof7030179 ◽

2021 ◽

Vol 7 (3) ◽

pp. 179

Author(s):

Kai P. Hussnaetter ◽

Magnus Philipp ◽

Kira Müntjes ◽

Michael Feldbrügge ◽

Kerstin Schipper

Keyword(s):

Protein Production ◽

Heterologous Protein ◽

Ustilago Maydis ◽

Downstream Processing ◽

Culture Broth ◽

Yeast Cells ◽

Heterologous Protein Expression ◽

Heterologous Proteins ◽

Regulatory Systems ◽

Unconventional Secretion

Heterologous protein production is a highly demanded biotechnological process. Secretion of the product to the culture broth is advantageous because it drastically reduces downstream processing costs. We exploit unconventional secretion for heterologous protein expression in the fungal model microorganism Ustilago maydis. Proteins of interest are fused to carrier chitinase Cts1 for export via the fragmentation zone of dividing yeast cells in a lock-type mechanism. The kinase Don3 is essential for functional assembly of the fragmentation zone and hence, for release of Cts1-fusion proteins. Here, we are first to develop regulatory systems for unconventional protein secretion using Don3 as a gatekeeper to control when export occurs. This enables uncoupling the accumulation of biomass and protein synthesis of a product of choice from its export. Regulation was successfully established at two different levels using transcriptional and post-translational induction strategies. As a proof-of-principle, we applied autoinduction based on transcriptional don3 regulation for the production and secretion of functional anti-Gfp nanobodies. The presented developments comprise tailored solutions for differentially prized products and thus constitute another important step towards a competitive protein production platform.

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