Direct conversion of Spirulina to ethanol without pretreatment or enzymatic hydrolysis processes

Aikawa, Shimpei; Joseph, Ancy; Yamada, R.; Izumi, Yuichi; Yamagishi, Takahiro; Mizutani, Fumio; Kawai, Hiroshi; Chang, Jo Shu; Hasunuma, Tomohisa; Kondo, Akihiko

doi:10.1039/c3ee40305j

Cited by 109 publications

(83 citation statements)

References 25 publications

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“…(Aikawa et al, 2013;Koutinas et al, 2014;Lee et al, 2014) Products of photoautotrophic growth Functional products from algae. Production of carotenoids, astaxanthin, high-value oils, vitamins, and proteins.…”

Section: Challengesmentioning

confidence: 99%

Challenges and opportunities for microalgae‐mediated CO₂ capture and biorefinery

Seth

Wangikar

2015

Biotech & Bioengineering

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Aquacultures of microalgae are frontrunners for photosynthetic capture of CO2 from flue gases. Expedient implementation mandates coupling of microalgal CO2 capture with synthesis of fuels and organic products, so as to derive value from biomass. An integrated biorefinery complex houses a biomass growth and harvesting area and a refining zone for conversion to product(s) and separation to desired purity levels. As growth and downstream options require energy and incur loss of carbon, put together, the loop must be energy positive, carbon negative, or add substantial value. Feasibility studies can, thus, aid the choice from among the rapidly evolving technological options, many of which are still in the early phases of development. We summarize basic engineering calculations for the key steps of a biorefining loop where flue gases from a thermal power station are captured using microalgal biomass along with subsequent options for conversion to fuel or value added products. An assimilation of findings from recent laboratory and pilot-scale experiments and life cycle analysis (LCA) studies is presented as carbon and energy yields for growth and harvesting of microalgal biomass and downstream options. Of the biorefining options, conversion to the widely studied biofuel, ethanol, and manufacture of the platform chemical, succinic acid are presented. Both processes yield specific products and do not demand high-energy input but entail 60-70% carbon loss through fermentative respiration. Thermochemical conversions, on the other hand, have smaller carbon and energy losses but yield a mixture of products.

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Section: Challengesmentioning

confidence: 99%

Challenges and opportunities for microalgae‐mediated CO₂ capture and biorefinery

Seth

Wangikar

2015

Biotech & Bioengineering

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“…They could also provide organic substrates for production of biofuel precursors by other organisms, particularly relevant on Mars where importing substrates from Earth would be impractical. For instance, as mentioned above, lysed cyanobacterial biomass has been used as a fermentation substrate for ethanol production in yeasts (Aikawa et al 2013;Möllers et al 2014). However, genetic engineering could remove the need for other organisms even for production of biofuel precursors which are not naturally produced by cyanobacteria in adequately large amounts -if at all.…”

Section: Producing Biofuelsmentioning

confidence: 99%

“…Note that these results are preliminary and that no optimization step (e.g., choice of a strain that can metabolize sucrose, alteration of culture conditions to modify cyanobacterial biomass's composition and/or more efficient extraction method) has yet been performed. Lysed cyanobacterial biomass has also been shown to be a suitable substrate for ethanol production in yeasts (Aikawa et al 2013;Möllers et al 2014). In lysogeny broth (LB), the most common growth medium for heterotrophic bacteria in laboratories, the concentration of fermentable sugars and sugar equivalents (sugar phosphates, oligosaccharides, nucleotides, etc.)…”

Section: Feeding Other Microorganismsmentioning

confidence: 99%

Sustainable life support on Mars – the potential roles of cyanobacteria

Verseux

Baqué

Lehto

et al. 2015

International Journal of Astrobiology

139

136

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Even though technological advances could allow humans to reach Mars in the coming decades, launch costs prohibit the establishment of permanent manned outposts for which most consumables would be sent from Earth. This issue can be addressed by in situ resource utilization: producing part or all of these consumables on Mars, from local resources. Biological components are needed, among other reasons because various resources could be efficiently produced only by the use of biological systems. But most plants and microorganisms are unable to exploit Martian resources, and sending substrates from Earth to support their metabolism would strongly limit the cost-effectiveness and sustainability of their cultivation. However, resources needed to grow specific cyanobacteria are available on Mars due to their photosynthetic abilities, nitrogen-fixing activities and lithotrophic lifestyles. They could be used directly for various applications, including the production of food, fuel and oxygen, but also indirectly: products from their culture could support the growth of other organisms, opening the way to a wide range of life-support biological processes based on Martian resources. Here we give insights into how and why cyanobacteria could play a role in the development of self-sustainable manned outposts on Mars.

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“…The hydrolysis products are fermented to ethanol using budding yeast. Additionally, extraction of glycogen from cyanobacteria is simpler than algae as it only requires breaking down the cyanobacterial cell wall with lysozyme (Aikawa et al, 2013;Möllers et al, 2014).…”

Section: Conversion Of Glycogen To Glucosementioning

confidence: 99%

The Enzymatic Conversion of Major Algal and Cyanobacterial Carbohydrates to Bioethanol

2016

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The production of fuels from biomass is categorized as first-, second-, or thirdgeneration depending upon the source of raw materials, either food crops, lignocellulosic material, or algal biomass, respectively. Thus far, the emphasis has been on using food crops creating several environmental problems. To overcome these problems, there is a shift toward bioenergy production from non-food sources. Algae, which store high amounts of carbohydrates, are a potential producer of raw materials for sustainable production of bioethanol. Algae store their carbohydrates in the form of food storage sugars and structural material. In general, algal food storage polysaccharides are composed of glucose subunits; however, they vary in the glycosidic bond that links the glucose molecules. In starch-type polysaccharides (starch, floridean starch, and glycogen), the glucose subunits are linked together by α-(1→4) and α-(1→6) glycosidic bonds. Laminarin-type polysaccharides (laminarin, chrysolaminarin, and paramylon) are made of glucose subunits that are linked together by β-(1→3) and β-(1→6) glycosidic bonds. In contrast to food storage polysaccharides, structural polysaccharides vary in composition and glycosidic bond. The industrial production of bioethanol from algae requires efficient hydrolysis and fermentation of different algal sugars. However, the hydrolysis of algal polysaccharides employs more enzymatic mixes in comparison to terrestrial plants. Similarly, algal fermentable sugars display more diversity than plants, and therefore more metabolic pathways are required to produce ethanol from these sugars. In general, the fermentation of glucose, galactose, and glucose isomers is carried out by wild-type strains of Saccharomyces cerevisiae and Zymomonas mobilis. In these strains, glucose enters glycolysis, where is it converted to pyruvate through either Embden-Meyerhof-Parnas pathway or Entner-Doudoroff pathway. Other monosaccharides must be converted to fermentable sugars before entering glycolysis. In contrast, microbial wild-type strains are not capable of producing ethanol from alginate, and therefore the production of bioethanol from alginate was achieved by using genetically engineered microbial strains, which can simultaneously hydrolyze and ferment alginate to ethanol. In this review, we emphasize the enzymatic hydrolysis processes of different algal polysaccharides. Additionally, we highlight the major metabolic pathways that are employed to ferment different algal monosaccharides to ethanol.

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Direct conversion of Spirulina to ethanol without pretreatment or enzymatic hydrolysis processes

Cited by 109 publications

References 25 publications

Challenges and opportunities for microalgae‐mediated CO₂ capture and biorefinery

Challenges and opportunities for microalgae‐mediated CO₂ capture and biorefinery

Sustainable life support on Mars – the potential roles of cyanobacteria

The Enzymatic Conversion of Major Algal and Cyanobacterial Carbohydrates to Bioethanol

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Direct conversion of Spirulina to ethanol without pretreatment or enzymatic hydrolysis processes

Cited by 109 publications

References 25 publications

Challenges and opportunities for microalgae‐mediated CO2 capture and biorefinery

Challenges and opportunities for microalgae‐mediated CO2 capture and biorefinery

Sustainable life support on Mars – the potential roles of cyanobacteria

The Enzymatic Conversion of Major Algal and Cyanobacterial Carbohydrates to Bioethanol

Contact Info

Product

Resources

About

Challenges and opportunities for microalgae‐mediated CO₂ capture and biorefinery

Challenges and opportunities for microalgae‐mediated CO₂ capture and biorefinery