Algal biofuels production, although theoretically attractive, faces a number of economic challenges—in particular, producing algae cost effectively at an agricultural scale. ALthough open ponds have been extensively studied and are considered to be the lowest cost and most scalable technologies for the production of algae, one of the challenges those systems face is contamination by algal predators and fast growing heterotrophs. Parasitic attacks can be devastating, destroying mass algae cultures in days. Unless contamination can be controlled, the researchers note, it is unlikely that open ponds will ever reach their potential in the production of algae for biofuel.

Numerous taxa in the basal fungi are primary parasites of the green algae that are major players in the biofuel industry. We have been exploring eukaryotic parasites attacking open ponds of Scenedesmus dimorphus grown for biofuel production in New Mexico, USA. Understanding these parasites’ life histories and phylogenetic relationships will help in the development of future strategies to control attacks in outdoor algal cultivation facilities.

We have identified one of these parasites as Amoeboaphelidium protococcarum Gromov and Mamkaeva, which at the time of our identification had not been characterized phylogenetically based on gene sequence analysis. Recently, however, another organism identified as A. protococcarum (strain X-5) from ponds at a more northern latitude (Kamchatka Peninsula, Russian Far East) has been phylogenetically analyzed and placed within the Cryptomycota clade. The Cryptomycota was erected based on phylogenetic analyses of gene sequences of two isolates of Rozella (an unwalled endoparasite of fungi and fungal-like organisms) and environmental sample.

The purposes of our study are to provide additional insights into the phylogenetic position, cultivation, and development of this plasmodial algal parasite and to compare our algal parasite isolate with that which Gromov and Mamkaeva described and contrast it with strain X-5 of Karpov et al. The results of our analyses demonstrate that these endoparasites of Scenedesmus are morphologically and molecularly more diverse than previously anticipated.

—Letcher et al.

The article provides a comprehensive study of the parasite challenge facing crop protection for scaled algae cultivation in open-pond systems. These results can provide a broader understanding and promote the development of sustainable management strategies for biofuel production, the authors suggest.

This article was prepared in collaboration by Robert C. McBride, Ph.D., Salvador Lopez, MSc, Craig Behnke, Ph.D., and Philip A. Lee, Ph.D., of Sapphire Energy; Peter M. Letcher, Ph.D., and Martha J. Powell, Ph.D., of the Department of Biological Sciences at the University of Alabama; and Robert Schmieder, Ph.D., of the Department of Computer Science and Computational Science Research Center at San Diego State University.

Identifying and overcoming crop protection challenges, from pest control to environmental factors, is critical to ensuring successful, scalable algae farming, and has long been a part of the research and development objective of Sapphire Energy. This collaborative study demonstrates the power of synergy when academic and industrial scientists work together for a common goal, and lays the groundwork for the better understanding and creation of innovative strategies that will facilitate algae biofuel production at commercial scale.

—Alex Aravanis, MD, Ph.D., chief science officer at Sapphire Energy

Resources

• Peter M. Letcher, Salvador Lopez, Robert Schmieder, Craig Behnke, Martha J. Powell, Robert C. McBride (2013) Characterization of Amoeboaphelidium protococcarum, an Algal Parasite New to the Cryptomycota Isolated from an Outdoor Algal Pond Used for the Production of Biofuel. PLoS ONE 8(2): e56232. doi: 10.1371/journal.pone.0056232