Building Better Algae Craig Marcus, Ph.D. Dept. of Environmental & Molecular Toxicology
Domestication of Algae as a New Crop Must develop a rapid process (corn first domesticated ~4000 B.C.) Requires a larger and improved informatics algae database Requires identification and characterization of a large array of diverse algae species Requires acquisition of extensive new data: Genomic Proteomic Lipidomic Metabonomic Requires development of new molecular and genetic tools for: breeding bioengineering agricultural engineering and cropping strategies New technologies for: Growth Harvesting Processing and production
Useful Algae Phenotypes Rapid Growth Optimized photosynthesis Optimal production of lipids, carbohydrates, proteins, etc. (food, fuel, fiber, pharmaceuticals, fertilizer, organic chemical feedstocks..) Optimized nutrient sources Optimized environmental adaptation (temperature, light, nutrients, saline, etc.) Optimized harvesting, cell lysis, product extraction Optimized CO 2 fixation Optimized bioremediation pathways Optimized for monoculture, co-culture Optimized Environmental Safety, Genetic Containment
Algae Biodiversity Unlike single traditional crop plants, Algae are a large heterogeneous group of organisms mostly eukaryotic Cell sizes from 1 100,000 μm Utilize light to fix carbon from CO 2, generate O 2 Require both specialized chemical and physical environments, as well as often unknown ecological environments (axenic cultures) Doesn t compete with food crops for fuel Grows rapidly primary input is (free, carbon neutral) solar energy High energy balance increases overall energy production (efficiency) Goal of close to neutral carbon footprint
Challenges to Developing new Algae Crops Must identify algae strains with desired traits No one single strain unlikely to be useful for multiple products in multiple environments Most desired traits are likely not naturally occurring phenotypes: production of high levels of desired molecules harvest efficiency and product recovery Thus will need to accomplish breeding and/or genetic modification with a rapid (evolutionary) time frame Long Range Synthetic Biology Approach
Need New Molecular Tools, Technologies and Reagents to Engineer Algae DNA Algae Genomes Nucleus Mitochondria Chloroplast Challenges in Algae Biotechnology HT Sequencing HT Screening Databases and Informatics Reporter Genes Marker Genes Selection Factors Promoters/Repressors Transformation Strategies Expression Vectors Cloning vectors Over expression, silencing of endogenous genes Heterologous expression Homologous promoters
Diverse Algae Genomes and Chloroplast Genomes (circular, average 140 kb and 110 genes) Chlamydomonas Genome and Metabolome Figure 1. Evolutionary relationships of representative photosynthetic eukaryotes. Synechocystis sp. Represents the pre-endosymbiotic ancestor of the chloroplast, and the tree shows branches from left to right for cyanelle containing algae (glaucocystophytes), red algae (rhodophytes), green algae (chlorophytes), and vascular plants (embryophytes). The plastid genomes are color-coded and proportional to the sizes generally found in that group. The major organisms derived from secondary endosymbiosis are shown in boxes. Plant Physiology, July 2002, Vol. 129, pp. 957 966 Fig. 1. A schematic of a Chlamydomonas cell (from transmission electron micrographs) showing the anterior flagella rooted in basal bodies, with intraflagellar transport (IFT) particle arrays between the axoneme and flagellar membrane, the basal cup-shaped chloroplast, central nucleus and other organelles. SCIENCE VOL 318 12 OCTOBER 2007
TRENDS in Biotechnology Vol.22 No.1 January 2004
Synthetic Biology Synthetic Biology entails the design and construction de novo of functional new biological units and systems as well as the redesign for improved or more useful functions of existing natural biological organisms. The difference between Synthetic Biology and Systems Biology is that systems biology merely studies the function of complex biological organisms while synthetic biology attempts to construct or re-engineer entire organisms or develop entirely new organisms de novo and from subunits of existing organisms. Synthetic Biology, as well as more traditional genetic engineering through molecular biology of existing organisms might be applied to generate useful new strains of algae and other single celled organisms for production of organic chemicals and biofuels.
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