Bioprocess En
257
Part B | 9.1
9. Bioprocess Engineering of Phototrophic
Marine Organisms
Gregory L. Rorrer
Phototrophic marine organisms, particularly photosynthetic marine algae, are a diverse source of
natural products ranging from lipid-based biofuels to pharmacologically-active compounds. The
engineered production of both biomass and natural products is accomplished within enclosed,
illuminated bioreactor systems called photobioreactors. This chapter describes the basic principles
of photobioreactor analysis and design, and
the biological factors that limit photobioreactor performance for the controlled cultivation of
phototrophic marine organisms. There are three
parts to this chapter. First, the quantitative growth
characteristics of photosynthetic marine organisms
in liquid cell suspension culture are described,
including the use of photosynthetic biomass stoichiometry to describe nutrient incorporation into
cellular biomass, and the combined effects of dissolved nutrient concentration and light intensity
on cell growth rate. Second, the basic elements
of photobioreactor design and operation are presented, focusing on models for predicting biomass
production in batch or continuous cultivation
modes within common photobioreactor configurations. Third, the limiting factors in photobioreactor
design and operation are critically assessed from
a quantitative point of view, focusing on light
and carbon dioxide transfer limitations, and their
effects on biomass production. Finally, future
directions for the design and applications of enclosed photobioreactors are overviewed.
9.1 Introduction
to Marine Process Engineering ............... 257
9.1.1 Phototrophic Marine Organisms:
A Diverse Source of Valuable
Natural Products .......................... 258
9.1.2 Marine Bioprocess Engineering
and the Cell Factory ..................... 259
9.2 Growth Characteristics
of Phototrophic Suspension Cultures ...... 261
9.2.1 Nutrient Requirements
and Photosynthetic Biomass
Stoichiometry .............................. 261
9.2.2 Specific Growth Rate .................... 264
9.3 Basic Elements
of Photobioreactor Design and Operation 267
9.3.1 Common Requirements ................ 267
9.3.2 Biomass Production
in Well-Mixed Batch
or Continuous Operation............... 267
9.3.3 Enclosed Photobioreactor
Configurations ............................. 270
9.4 Limiting Factors
in Photobioreactor Design and Operation 277
9.4.1 Five Steps
for Photobioreactor Design ........... 277
9.4.2 Light-Limited Growth ................... 277
9.4.3 Carbon Dioxide-Limited Growth .... 281
9.4.4 Process Scale-Up
and Other Limiting Factors ............ 286
9.4.5 Process Monitoring and Control ..... 287
9.4.6 Illustration of a Photobioreactor
Design Problem............................ 287
9.4.7 Design Needs Statement ............... 287
9.5 Future Directions for Process Scale
Enclosed Photobioreactors .................... 290
9.6 Notation. .............................................. 291
References................................................... 293
9.1 Introduction to Marine Process Engineering
Marine bioprocess engineering focuses on the design
and analysis of processes that manufacture valuable
compounds from marine organisms within an enclosed,
controlled environment. Marine bioprocesses use liv-
257
Part B | 9.1
9. Bioprocess Engineering of Phototrophic
Marine Organisms
Gregory L. Rorrer
Phototrophic marine organisms, particularly photosynthetic marine algae, are a diverse source of
natural products ranging from lipid-based biofuels to pharmacologically-active compounds. The
engineered production of both biomass and natural products is accomplished within enclosed,
illuminated bioreactor systems called photobioreactors. This chapter describes the basic principles
of photobioreactor analysis and design, and
the biological factors that limit photobioreactor performance for the controlled cultivation of
phototrophic marine organisms. There are three
parts to this chapter. First, the quantitative growth
characteristics of photosynthetic marine organisms
in liquid cell suspension culture are described,
including the use of photosynthetic biomass stoichiometry to describe nutrient incorporation into
cellular biomass, and the combined effects of dissolved nutrient concentration and light intensity
on cell growth rate. Second, the basic elements
of photobioreactor design and operation are presented, focusing on models for predicting biomass
production in batch or continuous cultivation
modes within common photobioreactor configurations. Third, the limiting factors in photobioreactor
design and operation are critically assessed from
a quantitative point of view, focusing on light
and carbon dioxide transfer limitations, and their
effects on biomass production. Finally, future
directions for the design and applications of enclosed photobioreactors are overviewed.
9.1 Introduction
to Marine Process Engineering ............... 257
9.1.1 Phototrophic Marine Organisms:
A Diverse Source of Valuable
Natural Products .......................... 258
9.1.2 Marine Bioprocess Engineering
and the Cell Factory ..................... 259
9.2 Growth Characteristics
of Phototrophic Suspension Cultures ...... 261
9.2.1 Nutrient Requirements
and Photosynthetic Biomass
Stoichiometry .............................. 261
9.2.2 Specific Growth Rate .................... 264
9.3 Basic Elements
of Photobioreactor Design and Operation 267
9.3.1 Common Requirements ................ 267
9.3.2 Biomass Production
in Well-Mixed Batch
or Continuous Operation............... 267
9.3.3 Enclosed Photobioreactor
Configurations ............................. 270
9.4 Limiting Factors
in Photobioreactor Design and Operation 277
9.4.1 Five Steps
for Photobioreactor Design ........... 277
9.4.2 Light-Limited Growth ................... 277
9.4.3 Carbon Dioxide-Limited Growth .... 281
9.4.4 Process Scale-Up
and Other Limiting Factors ............ 286
9.4.5 Process Monitoring and Control ..... 287
9.4.6 Illustration of a Photobioreactor
Design Problem............................ 287
9.4.7 Design Needs Statement ............... 287
9.5 Future Directions for Process Scale
Enclosed Photobioreactors .................... 290
9.6 Notation. .............................................. 291
References................................................... 293
9.1 Introduction to Marine Process Engineering
Marine bioprocess engineering focuses on the design
and analysis of processes that manufacture valuable
compounds from marine organisms within an enclosed,
controlled environment. Marine bioprocesses use liv-