Computer Aided Chemical Engineering
Volume: 38 Pages: 325-330
Master Degree Thesis
Plant Physiol Biochem Link
Xu Y, Ibrahim IM, Harvey PJ.
Published: MAY 17 2016
Biobased Future, Nr. 3, p15
Conference Paper Link
M.Psycha, K.Pyrgakis, S.Theologou, A.C.Kokossis
Computer Aided Chemical Engineering Link
Melina Psycha, Kostantinos Pyrgakis, Patricia J. Harvey, Ami Ben-Amotz, A. Keith Cowan, Antonis C. Kokossis
The study discusses the development of an integrated process that addresses the coproduction of glycerol, β-carotene and proteins from microalgae biomass using a multitude of solvents and scoping to reduce energy consumption. An evolutionary approach is adopted in order to establish feasible and sustainable flowsheeting. Process integration is applied to target efficiency scoping reviewing thermal integration and the use of alternative separation schemes. The analysis reviews economic benefits as well as the impact of process integration in securing the viability of the incentive.
P.J.Harvey, M.Psycha, A.Kokossis, A.L.Abubakar, V.Trivedi, R.Swamy, A.K.Cowan, D.Schroeder, A.Highfield, G.Reinhardt, S.Gartner, J.McNeil, P. Day, M.Brocken, J.Varrie, A Ben-Amotz
ETA-Florence Renewable Energies
Our aim is to increase the range of commercially viable biofuels by developing a low-cost system for producing industrial quantities of glycerol from the halophytic microalga, Dunaliella, cultivated on saline water. Glycerol can be combusted at very high efficiencies and with very low emissions without chemical alteration or the addition of combustion enhancers using a new commercial CHP technology based on the McNeil cycle, and holds the key to developing an entirely new, environmentally-sustainable biofuel industry sector. Glycerol will also serve as an intermediate to replace various fossil oil-based bulk chemicals in the biorefineries of the future. Glycerol is currently available from biodiesel manufacture, but is also synthesised de novo by natural halophytic microalgae that grow in highly saline environments (salt pans and desalination non-potable waters) across the globe. In this paper new strains of halophytic microalgae from Namibia were characterised for glycerol productivity and the data used in engineering models to optimise production and process designs. Our preliminary data indicate that in water-based biorefineries the economic potential of the venture will improve dramatically as one shifts from single-product into multiproduct processes. Based on current prices of glycerol, both glycerol and β-carotene need to be extracted from Dunaliella for profitability.
PLOS Biology Link
Keeling PJ, Burki F, Wilcox HM, Allam B, Allen EE, Amaral-Zettler LA, Armbrust EV, Archibald JM, Bharti AK, Bell CJ, Beszteri B, Bidle KD, Cameron CT, Campbell L, Caron DA, Cattolico RA, Collier JL, Coyne K, Davy SK, Deschamps P, Dyhrman ST, Edvardsen B,
Microbial ecology is plagued by problems of an abstract nature. Cell sizes are so small and population sizes so large that both are virtually incomprehensible. Niches are so far from our everyday experience as to make their very definition elusive. Organisms that may be abundant and critical to our survival are little understood, seldom described and/or cultured, and sometimes yet to be even seen. One way to confront these problems is to use data of an even more abstract nature: molecular sequence data. Massive environmental nucleic acid sequencing, such as metagenomics or metatranscriptomics, promises functional analysis of microbial communities as a whole, without prior knowledge of which organisms are in the environment or exactly how they are interacting. But sequence-based ecological studies nearly always use a comparative approach, and that requires relevant reference sequences, which are an extremely limited resource when it comes to microbial eukaryotes.
In practice, this means sequence databases need to be populated with enormous quantities of data for which we have some certainties about the source. Most important is the taxonomic identity of the organism from which a sequence is derived and as much functional identification of the encoded proteins as possible. In an ideal world, such information would be available as a large set of complete, well-curated, and annotated genomes for all the major organisms from the environment in question. Reality substantially diverges from this ideal, but at least for bacterial molecular ecology, there is a database consisting of thousands of complete genomes from a wide range of taxa, supplemented by a phylogeny-driven approach to diversifying genomics. For eukaryotes, the number of available genomes is far, far fewer, and we have relied much more heavily on random growth of sequence databases, raising the question as to whether this is fit for purpose.
22nd EU Biomass Conference & Exibition Link
Psycha, M., Pyrgakis, K., Harvey, P.J., Ben-Amotz, A., Keith Cowan, A., Kokossis, A.C.
Biorefineries typically refer to lignocellulosic feedstock as they are available from agricultural activities, residues, waste organics or forestry supplies. There is much less attention to water substrates from micro-algae and macro-algae systems that feature alternative paths to products, involve competitive chemistries and require co-production of chemicals to remain feasible. A notable case relates to halophytic Dunaliella cultures capable to convert CO2into a multitude of products. One needs to select Dunaliella for its extraordinary tolerance to salt stress establishing it as one of the few organisms that can survive in extreme environments.
The paper discusses the development of an integrated process that addresses the co-production of glycerol, b-carotene and proteins using a multitude of solvents and scoping to reduce energy consumption. The reference case refers to an industrial pilot set up to operate with the use of ethanol as solvent and produces 3.5 tones biomass per year. The cultivation of Dunaliella takes place in the cultivation pond (0.5 Ha) and after harvesting, osmotic shock is induced to the cells resulting in the accumulation of glycerol and β-carotene. Their extraction is achieved by breaking up the cell walls with the use of ethanol in a high concentration. The mixture of ethanol/water/glycerol is distilled for ethanol recycling and refinement of glycerol, while β-carotene is extracted from the remaining mixture by using hexane as solvent. The energy intensive separation of the ethanol/water/glycerol mixture raises questions regarding the sustainability of the process.
The paper discusses implications as the process develops from a single-product plant to a multi-product process with co-production of specialties and the valorization of by-products. The analysis reviews economic benefits as well as the impact of process integration in securing the viability of the incentive. Process integration is applied to target efficiency scoping reviewing thermal integration, and the use of alternative separation schemes including azeotropic distillation. The work uses a supertask model to review thermally coupled columns including prefractionators, Petlyuk columns, side strippers and side Rectifiers featuring sloppy splits, and side draws. The work concludes that, even though single-product processes are not economically viable (with or without integration), the multi-product process can benefit dramatically from process integration (38% reduction in energy use) and can yield a sustainable and profitable process.