The impact of genomics on engineering and breeding of microalgae for value-added traits

The PACE (Producing Algae for Coproducts and Energy) algal biofuels consortium is tasked with developing leading-edge technologies to; 1) reduce the cost of producing biofuels from algae from $8.00 to < $5.00 gallon gasoline... [ view full abstract ]

The PACE (Producing Algae for Coproducts and Energy) algal biofuels consortium is tasked with developing leading-edge technologies to; 1) reduce the cost of producing biofuels from algae from $8.00 to < $5.00 gallon gasoline equivalent, and 2) to enhance the sustainability of algal biofuel production systems to qualify as advanced biofuel feed stocks. Our target biofuel production strain is Chlorella sorokiniana. Recently, the genomes of several C. sorokiniana isolates have been sequenced and found to be highly divergent. These genome sequences have served as the foundation for designing and developing genetic transformation and breeding systems. Recently, we achieved a significant milestone towards routine engineering of C. sorokinina with the development of transformation protocols based on enhancing double-stranded breaks in chromosomes to facilitate transgene integration. In addition, the genome information has allowed us to identify unique genetic markers that will be used for the first time for marker assisted breeding for select trait enhancement in a commercial alga strain. Related to this effort, we have observed active gametogenesis and mating in C. sorokiniana cultures indicating that the genetic stability of algae must be considered when selecting for or engineering advanced traits. Recently, we have developed strategies for developing inbred hybrids with the added benefit of enhanced genetic stability associated with a introduction of mutations leading to sterility. These and other aspects of the impacts of genomics on metabolic engineering of algae for value-added traits will be discussed.