Green biologics: The algal chloroplast as a platform for making biopharmaceuticals

Taunt, Henry N.; Stoffels, Laura; Purton, Saul

doi:10.1080/21655979.2017.1377867

Cited by 67 publications

(58 citation statements)

References 40 publications

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“…Therefore, in the last two decades, an increasing research effort has been put into developing robust, alternative production hosts. Plant and algae-based expression systems are envisioned as a valid, low-cost solution for producing therapeutics in countries and areas that lack resources for costly mammalian-based fermentation systems (Taunt et al, 2018), with the advantage of being immune to most pathogens and contaminations that affect animal hosts (Specht and Mayfield, 2014). In this search, it has been demonstrated the suitability of C. reinhardtii to produce -predominantly in the chloroplast -functional recombinant therapeutics, including a fully assembled human antibody, immunoglobulin G (IgG) (Tran et al, 2009), vaccine subunits (Gregory et al, 2013), vaccine antigens (Demurtas et al, 2013), immunoconjugated cytotoxins for cancer targeted treatments (Tran et al, 2013), and single domain antibodies (VHH) (Barrera et al, 2015).…”

Section: High-value Productsmentioning

confidence: 99%

Emerging Technologies in Algal Biotechnology: Toward the Establishment of a Sustainable, Algae-Based Bioeconomy

et al. 2020

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Mankind has recognized the value of land plants as renewable sources of food, medicine, and materials for millennia. Throughout human history, agricultural methods were continuously modified and improved to meet the changing needs of civilization. Today, our rapidly growing population requires further innovation to address the practical limitations and serious environmental concerns associated with current industrial and agricultural practices. Microalgae are a diverse group of unicellular photosynthetic organisms that are emerging as next-generation resources with the potential to address urgent industrial and agricultural demands. The extensive biological diversity of algae can be leveraged to produce a wealth of valuable bioproducts, either naturally or via genetic manipulation. Microalgae additionally possess a set of intrinsic advantages, such as low production costs, no requirement for arable land, and the capacity to grow rapidly in both large-scale outdoor systems and scalable, fully contained photobioreactors. Here, we review technical advancements, novel fields of application, and products in the field of algal biotechnology to illustrate how algae could present high-tech, low-cost, and environmentally friendly solutions to many current and future needs of our society. We discuss how emerging technologies such as synthetic biology, highthroughput phenomics, and the application of internet of things (IoT) automation to algal manufacturing technology can advance the understanding of algal biology and, ultimately, drive the establishment of an algal-based bioeconomy.

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Section: High-value Productsmentioning

confidence: 99%

Emerging Technologies in Algal Biotechnology: Toward the Establishment of a Sustainable, Algae-Based Bioeconomy

et al. 2020

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“…Large-scale cultivation of transgenic lines in a 'hanging bag' photobioreactor Scale-up performance was assessed in a hanging bag photobioreactor system originally developed by the Cawthron Institute, New Zealand (Taunt et al 2017). The NNV + PtxD strain was grown in single-use polythene tubular bags (provided by Supreme Health, New Zealand), each containing 20 l of TAP or TA-Phi medium.…”

Section: Functional Analysis Of Ptxd Transgenic Linesmentioning

confidence: 99%

“…The NNV transformant is part of an on-going 'proof-of-concept' project as a cheap, oral vaccine for the farmed fish industry (Charoonnart et al 2018). However, production of algal biomass for applications such as feed additives for the aquaculture, poultry and other livestock sectors, can be challenging, not least because of the problems of contamination in low-cost photobioreactor systems (Taunt et al 2017). To demonstrate the practical use of the ptxD system as a cropprotection tool, we carried out a large-scale cultivation of the NNV + PtxD transgenic line in a hanging-bag system.…”

Section: Large-scale Cultivation Under Non-sterile Conditions Illustrmentioning

confidence: 99%

“…The microalgal chloroplast is an attractive industrial biotechnology platform for synthesis of recombinant products such as bioactive metabolites and therapeutic proteins (Gimpel et al 2015a;Taunt et al 2017). Of the handful of microalgal species for which transformation of the chloroplast genome has been reported, the most advanced is the freshwater chlorophyte Chlamydomonas reinhardtii (Purton et al 2013).…”

Section: Introductionmentioning

confidence: 99%

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The phosphite oxidoreductase gene, ptxD as a bio-contained chloroplast marker and crop-protection tool for algal biotechnology using Chlamydomonas

Changko

Rajakumar

Young

et al. 2019

Appl Microbiol Biotechnol

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Edible microalgae have potential as low-cost cell factories for the production and oral delivery of recombinant proteins such as vaccines, anti-bacterials and gut-active enzymes that are beneficial to farmed animals including livestock, poultry and fish. However, a major economic and technical problem associated with large-scale cultivation of microalgae, even in closed photobioreactors, is invasion by contaminating microorganisms. Avoiding this requires costly media sterilisation, aseptic techniques during setup and implementation of 'crop-protection' strategies during cultivation. Here, we report a strain improvement approach in which the chloroplast of Chlamydomonas reinhardtii is engineered to allow oxidation of phosphite to its bioavailable form: phosphate. We have designed a synthetic version of the bacterial gene (ptxD)-encoding phosphite oxidoreductase such that it is highly expressed in the chloroplast but has a Trp→Opal codon reassignment for bio-containment of the transgene. Under mixotrophic conditions, the growth rate of the engineered alga is unaffected when phosphate is replaced with phosphite in the medium. Furthermore, under non-sterile conditions, growth of contaminating microorganisms is severely impeded in phosphite medium. This, therefore, offers the possibility of producing algal biomass under non-sterile conditions. The ptxD gene can also serve as a dominant marker for genetic engineering of any C. reinhardtii strain, thereby avoiding the use of antibiotic resistance genes as markers and allowing the 'retro-fitting' of existing engineered strains. As a proof of concept, we demonstrate the application of our ptxD technology to a strain expressing a subunit vaccine targeting a major viral pathogen of farmed fish.

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“…Current commercial production of recombinant molecules such as therapeutic proteins and bioactive metabolites relies almost exclusively on heterotrophic cell platforms such as bacteria, yeasts and mammalian cell lines [1]. However, there is increasing interest in the exploitation of eukaryotic microalgae as low-cost, phototrophic platforms [2,3]. Green algal species such as Chlamydomonas reinhardtii, Chlorella vulgaris and Haematococcus pluvialis can be cultivated at scale in simple photobioreactor systems using a basic growth medium [4,5].…”

mentioning

confidence: 99%

Multigenic engineering of the chloroplast genome in the green alga Chlamydomonas reinhardtii

Larrea-Álvarez

Purton

2020

Microbiology

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The chloroplast of microalgae such as Chlamydomonas reinhardtii represents an attractive chassis for light-driven production of novel recombinant proteins and metabolites. Methods for the introduction and expression of transgenes in the chloroplast genome (=plastome) of C. reinhardtii are well-established and over 100 different proteins have been successfully produced. However, in almost all reported cases the complexity of the genetic engineering is low, and typically involves introduction into the plastome of just a single transgene together with a selectable marker. In order to exploit fully the potential of the algal chassis it is necessary to establish methods for multigenic engineering in which many transgenes can be stably incorporated into the plastome. This would allow the synthesis of multi-subunit proteins and the introduction into the chloroplast of whole new metabolic pathways. In this short communication we report a proof-of-concept study involving both a combinatorial and serial approach, with the goal of synthesizing five different test proteins in the C. reinhardtii chloroplast. Analysis of the various transgenic lines confirmed the successful integration of the transgenes and accumulation of the gene products. However, the work also highlights an issue of genetic instability when using the same untranslated region for each of the transgenes. Our findings therefore help to define appropriate strategies for robust multigenic engineering of the algal chloroplast.

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Green biologics: The algal chloroplast as a platform for making biopharmaceuticals

Cited by 67 publications

References 40 publications

Emerging Technologies in Algal Biotechnology: Toward the Establishment of a Sustainable, Algae-Based Bioeconomy

Emerging Technologies in Algal Biotechnology: Toward the Establishment of a Sustainable, Algae-Based Bioeconomy

The phosphite oxidoreductase gene, ptxD as a bio-contained chloroplast marker and crop-protection tool for algal biotechnology using Chlamydomonas

Multigenic engineering of the chloroplast genome in the green alga Chlamydomonas reinhardtii

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