Final Report Summary - ALGFUEL (Biodiesel production from microalgae) Microalgae can provide high biomass and lipid production in locations where they will not compete with edible crops, for instance because of the ability of some species to tolerate and grow in extreme environments. There has been a great deal of work in this field already, but with a very limited range of species, most of which have been cultivated species as a food source for fish, crustacean and bivalve production. This project on microalgal growth and biochemical composition was designed to enhance the possibility of producing biodiesel and other useful products from microalgae in Europe. Specifically, it focused on: 1. identifying and isolating new local species and strains that are suitable candidates for biodiesel production; 2. measuring growth and lipid composition; 3. improving knowledge of microalgal triacylglyceride (TGA)s, a group of fatty compounds that are particularly important for potential biofuel production; and 4. optimising TAG productivity in microalgal cultures. This project was conducted by Dr Asher Wishkerman and coordinated by Dr Rosa Trobajo within the Aquatic Ecosystems unit at Institute of Agriculture and Food Research and Technology (IRTA). An important aspect of the project was the isolation into clonal culture of a diatom Nitzschia lembiformis, with very promising growth characteristics (tolerance to hypersaline conditions),which was isolated from benthic algal communities in the La Trinitat salt works, located in the Ebro Delta, Catalonia, Spain. Essential to any potential biotechnological use of a microalga is a full evaluation of the conditions that optimise growth. Therefore, experiments were conducted involving a variety of growth media. These showed that widely used 'Walne' medium provides better growth conditions than either Enriched seawater artificial water (ESAW) or one of the other commonly used media 'f/2'. Characterisation of the lipid composition of N. lembiformis gave a total lipid content of almost 20 % and revealed a great variety of fatty acids (23 kinds), which is a feature shared with other diatoms. Assessments of growth potential, together with lipid analysis, indicate that N. lembiformis could be a good candidate for biotechnology, including lipid production. In order to provide further data on microalgae already used commonly in aquaculture, studies were made of Phaeodactylum tricornutum, Chaetoceros calcitrans and Isochrysis galbana, because their cultivation is well understood and because of their use in the aquaculture unit of the institute where the work was performed. In addition, a particular focus was microalgae from Class Cryptophyceae. These microalgae are of great importance in aquaculture but extremely understudied in relation to their potential for biofuel. Two Rhodomonas species (R. salina and R. lens) were cultivated in different media (involving different chloride and nitrate concentrations) in order to understand more about the main mechanisms driving TAG formation. Enhanced TAG content was observed at high chloride concentrations in R. salina, consistent with other studies showing increases in TAGs when plants are stressed, but growth was low at the highest chloride concentration, the best growth occurring in the low chloride ESAW medium. Overall, useful progress was made in understanding that may aid exploitation of the microalgae currently used in biotechnology and in developing a new, potentially valuable microalga (Nitzschia lembiformis) for lipid production, in European algal biofuel research and development, and in the aquaculture industry. Further research will be needed, however, especially to see how the obtained results can be scaled up to industrial levels. During the project, many opportunities were taken to acquire and develop skills in algal isolation and culture (at different scales, from small flasks to multilitre batches), biochemical analysis and interpretation, morphometrics, and statistical analysis and modelling.
