An Engineered Community Approach for Industrial Cultivation of Microalgae

Abstract

Although no species lives in isolation in nature, efforts to grow organisms for use in biotechnology have generally focused on a single-species approach, particularly where a product is required at high purity. In such scenarios, preventing the establishment of contaminants requires considerable effort that is economically justified. However, for some applications in biotechnology where the focus is on lower-margin biofuel production, axenic culture is not necessary, provided yields of the desired strain are unaffected by contaminants. In this article, we review what is known about interspecific interactions of natural algal communities, the dynamics of which are likely to parallel contamination in industrial systems. Furthermore, we discuss the opportunities to improve both yields and the stability of cultures by growing algae in multi-species consortia.

Long-Term Cultivation of Algae in Open-Raceway Ponds: Lessons from the Field

“…[28][29][30] Stable, long-term, continuous cultivation of a single target strain cannot be accomplished without the ability to control biological contaminants (i.e., pests, weeds, and disease, collectively referred to here as pests). 31,32 Losses to grazers have been estimated at 20% -10%, and population crashes are of particular concern, since complete loss of even a single pond in an array can dramatically impact overall facility productivity and yield. 33,34 Rotifers, ciliates, and amoeba were commonly found grazers at the Columbus farm.…”

“…6 Pests are somewhat strain-dependent; for example, strains with smaller cell size are more susceptible to certain grazers than strains of larger cell size, and strains with defensive morphology mechanisms are less sensitive to gape-limited grazers than those that lack such a defense. 32,36 Pests have also been seasonal. Warmer seasons bring a variety of pest types; but in winter, pests have been limited to invasions of non-target algae (weeds) rather than grazers or disease.…”

“…35 Managing the water chemistry of the hydraulic system such that the target algal strain is at an advantage compared to invasions by non-target, weedy algae or other pest organisms is an important IPM practice for algal cultivation. 32 There are already a number of examples of this strategy in algal cultivation, and water chemistry management can be used both as a preventive measure (target strain advantage) or a reactive measure (pest disadvantage). 23,28,39,41 Beneficial ecology can also be utilized against invading pests.…”

Managing nutrients and system operations for biofuel production from freshwater macroalgae

“…Nonetheless, the degree of scale-up that will be required to achieve the bulk growth of algae for fuels poses a significant number of challenges, ranging from the high capital, energy, and other resource costs of establishing and maintaining the cultivation and processing systems, to problems associated with biological contamination by pests and non-target organisms [33,35,36].…”

Microalgae biorefineries: The Brazilian scenario in perspective

“…These strains will probably be specific for each substrate/ location as indicated by the higher productivities obtained with indigenous microalgae grown in produced water [64,65] shown in Table 2. In addition, in order to maximize microalgae culture resilience and productivity, the use of engineered polycultures where diverse organisms are grown together in a synergistic manner should be considered [89]. Also promising is the use of breeding and genetic engineering (GMO) techniques to develop strains with traits that provide crop protection and fast efficient growth [reviewed in 15,90].…”