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Contents

  1. 1 Algae Biofuels
    1. 1.1 Reactor Design and Operational strategies
    2. 1.2 Molecular Biology
    3. 1.3 Grants
      1. 1.3.1 NSF: Petroleum-Based Algal Oils
      2. 1.3.2 NSF SBIR Phase 1
    4. 1.4 PEOPLE
    5. 1.5 Papers / Patents / Presentations:  
Algae Biofuels

An algal production platform aimed at CO2 sequestration and waste-water remediation for biomass, lipids, and hydrocarbon production has been under deveopment at Curtis lab for over 6 years. While at Harvard for his 2006-2007 sabbatical, Dr. Curtis assisted GreenFuel Technologies for photobioreactor systems developed at Penn State, though parted ways with the company to avoid intellectual-property issues to continue the effort with a passionate team of students.  In 2008, Dr. Curtis teamed up with the Chappell Laboratory to examine the metabolic pathways that produce C34 hyrdrocarbons in Botryococcus braunii and recieved an NSF Grant noted below.  


Reactor Design and Operational strategies

There has recently been a flourish of startup companies claiming various superior processes and photobioreactors for algae production. Many of these designs have obvious or hidden limitations that have significant impact – not only on productivity, but also on the cost of operation. The following rationale includes considerations of the entire algae biomass production process that needs to be critically analyzed to minimize processing costs. Photobioreactor designs are often divided into open pond and enclosed photobioreactors. Reactors should be more appropriately divided into high-density/intensity and low-density/intensity photobioreactors. In order to achieve low cost biomass production, energy use must be minimized. Using this perspective, the bioreactor shown in figure 1 is proposed as the most promising high-intensity photobioreactor system to implement for the production of low cost biomass. Application of a minimum thickness turbulent mixed film in conjunction with light-limited high-density algae growth achieves maximum productivity.

The rationale for developing the proposed photobioreactor system is based on light physics, algae physiology and, most importantly, economic constraints that have resulted in the proliferation of poorly conceived bioreactor systems that have little hope of achieving economic feasibility based on simple mass and energy balance principles. The proposed bioreactor is discussed below in the context of the energy required to carry out critical basic bioreactor operation; specifically, fluid pumping, gas compression, algae dewatering, and energy removal.
Schematic of algae to fuel process based on alternative technologies for field-scale
implementable nutrient delivery, photobioreactor growth oil and biomass recovery and processing.

Algae is grown as a suspension that trickles-down a screen to induce turbulent mixing in a simple geometry that promotes efficient photon use by avoiding a surface that can foul between the algae and the light, to support densities of 30+g/L biomass correlating to some of the highest productivities found in literature irrespective of the intrinsic growth rate among various stains of algae. We have demonstrated that CO2 fertilization can be accomplished in the evaporative water make-up saturated with nearly pure CO2. This avoids prohibitive costs of heat removal and gas compression on agricultural scales. This approach also avoids the capital expense and safety/permitting issues of a light blocking ‘green-house’ enclosures and use of existing scrubbing technologies to provide concentrated CO2. Turbulent ultra-thin film culture will permit the highest possible cell concentrations, which will facilitate low-cost down stream dewatering and reduce ‘hydraulic load’ costs throughout the process.

Molecular Biology

The over-arching research objective of the current proposal is to fully characterize the pathway for tetramethyl-triterpene biosynthesis, and to assess novel strategies for the genetic and process engineering of these natural products into algae. This project leverages the Principal Investigators (PIs) recent success in isolating the genes coding for the biosynthesis of rather unique branched-chain, unsaturated hydrocarbons (methylated triterpenes), and the development of novel tools to engineer metabolic shunts for high-level terpene production in terrestrial plants. The proposed collaborative research brings together genetic engineering proof-of-principle with novel process engineering advances in algae culture required to evaluate these alternative platforms of agri-culture and alga-culture for commodity-scale displacement of fossil fuels with renewable, green-house-gas neutral biofuels.

We are proposing to produce methylated triterpenes in transgenic algae as a proof-of-principle that demonstrates high-value natural products can indeed be produced in a robust, renewable and sustainable platform.
  We will perform the initial work with transgenic Chlamydomonas reinhardtii because of the available tools and speed with which this species can be genetic engineered. This will set the stage for evaluating alternative species such as terrestrial plants or marine algae which are more difficult to manipulate. 

Although production and extraction processes exist for terrestrial plants, comparable agricultural-scale systems have not been developed for algae. The proposed work therefore includes simultaneous development of photobioreactor design and operational optimization work that are needed to assess the feasibility of these alternative production platforms. A future collaboration will evaluate these algal-derived hydrocarbons as alternative fuel feedstocks with Dr. Mark Crocker at the UK Center for Applied Energy Research, an expert in the hydrocarbon catalytic cracking process and fuel characterization [Shumaker et al., 2007]. The potential of our proposal thus hinges on the biosynthesis of methylated triterpenes by genetic engineered algae, combined with development of algal cultural practices as they interface with downstream processing for extraction and conversion to aliphatic and aromatic precursors, and whether these aims can ultimately be brought together on a scale sufficient to meet the demands for a high volume commodity like liquid transportation fuels.

Grants

NSF: Petroleum-Based Algal Oils

NSF Grant Site (0828648)






NSF SBIR Phase 1

NSF Grant Site (0945592)





PEOPLE

Curtis Lab Research Team:  Graduate Students:   Lisa Grady, Amalie Tuerk,   Manuel Escotet, Megerle Scherholz, Waqas Khatri, ,
Penn State Undergraduate Students:   Rachel Arndt, Chelsea Berry, Doug Middleton, Fahad Taimur, Jacki Guo, Adam Nebzydoski, Amber Stahl,  Jillian Newhall, Jinwoo Kim, Justin Stover, Kyle Waskiewicz, Shannon Connelly, Steven Gabauer, Taesup Lee, Tamara Siskind,    Patrick Hillery, Robert Hendrix, Justin Yoo,  John Myers, Christine Taylor. 
Technitions, Interns, Volunteers & Experts:   Ryan Johnson, Tim Miskimmin (Canterberry, New Zealand), Lalit Darunte (IIT Deli), Shalini Saxena (Rose Hulman), Emily Voigt (Kansas State), John Michael (Miami University, OH).  

Chappell Lab Research Team:  Joe! (the legend =),  Graduate Students: Tom Niehaus, Steve 
Technition:  Scott Kinison  

Papers / Patents / Presentations:  

  1. Dirk Link, Amalie Tuerk. "Overall Energy Considerations for Algae Species Comparison and Selection in Algae-to-Fuels Processes." Alternative Energy NOW Conference, Lake Buena Vista, FL, February 23, 2011.
  2. Amalie Tuerk*, Wayne R. Curtis.  "Algae-Based Hydrocarbon Production." USDA Research Center, Philadelphia, PA, April 23, 2010.
  3. Waqas Khatri, Steve Gabauer, Joeseph Chappell, Wayne Curtis "Algae-Based Hydrocarbon Production", AIChE Annual Meeting, Philadelphia, PA, Nov. 18, 2008.
  4. Stephen Gabauer, Thomas D. Niehaus, Waqas Khatri, Joeseph Chappell, Wayne Curtis. "Genetic Engineering Hydrocarbon Production in Algae", AIChE Annual Meeting, Philadelphia, PA, Nov. 19, 2008.