Production of Bio-hydrogen by Microorganism

1. Production of Bio-hydrogen by Microorganism Group 2: CHUAY JIE QI OW CHOON LIN FITRI HIDAYAH AKMAL

2. Fact of Fossil Fuel • Non-renewable energy • Negative impact on environment • Excessive global climate change • Emission of greenhouse pollutant Source: http://harmonscience6.wikispaces.com/; fossilfuelsenergy.weebly.com; www.theguardian.com

3. Introduction to Hydrogen Fuel • Act as energy carrier • High energy content • Almost 3x greater than H-C fuels • It can be operate at ambient temperature and pressure with minimum energy consumption • Clean renewable energy • Sustainably: contribution to the world economic growth • Environmentally friendly • Most abundant element

4. Raw Materials for H₂ Production Source:www.tullowoil.com; reachingutopia.com; globalresourceadvisorsllc.com; www.biologyexams4u.com

5. Microorganisms Produce H₂ • Plant base: Green Microalgae • Chlamydomonas sp. • Produce x2 efficient compared to wild type strain for PS I • Microbe base: Cyanobacteria • Anabaena variabilis ATCC 29413 Source: www.fytoplankton.cz Source: microbewiki.kenyon.edu

6. Other Information: Registration Product Strain used for Hydrogen production Cyanobacteria 3 4 2 5 1 • Production can undergo • i) Direct photolysis • ii) Indirect photolysis • Use two distinct enzymes to generate H2: • i) Nitrogenase • ii) Hydrogenase • Unique prokaryotes with diverse range properties • Species divided into 3 groups: • i) Heterocystous • ii) Non- heterocystous • iii) Marine • Ideal microbes for hydrogen production Source: http://waynesword.palomar.edu/

7. Factors affecting Hydrogen production in Cyanobacteria

8. Role of environmental factors

9. Condition of production • Growth of algae in photobioreactors (PBR) • Light source and hydrodynamics – conditions affect algae growth • Must be in closed system – to prevent hydrogen escape and facilitate collection of gas • Design must allow for easy sterilization • Provide high surface area to volume ratio

10. Types of PBR

13. Method to Produce H₂ • Biophotolysis • Photo-fermentation • Photosynthesis process • Dark-fermentation • Anaerobic process: Organic  H₂ • Better than photo-fermentation: not depend on sunlight as energy source, can perform continuous process of hydrogen production • Hybrid Biological Hydrogen Production • Electrolysis : continuous produce H₂ assisted electron exchange by bacteria • Adv: ↓ Energy needed to produce H₂, electrochemical process is not limited only to carbohydrates Bacteria

14. Biophotolysis • Definition: • Plant-type photosynthesis process by microorganism to split waster to H₂ with light in anaerobic condition. Enzyme: Hydrogenase Bacteria: Green algae/cyanobacteria Sunlight CO₂

15. Advantages of Biophotolysis • No requirement of adding substrate as nutrients • Hydrogen produced: • Does not emit greenhouse gas • Abundant for avaibility • Renewable energy • H₂ used in fuel cell to generate electricity

16. Overview of Production & Utilization of H₂

17. Production of H₂ Direct Biophotolysis Hydrogenase H₂

18. Type of Hydrogenase • FeFe-hydrogenase • Catalyses the reversible oxidation of molecular hydrogen.

19. Contd.. • NiFe-bidirectional hyrogenase • Metal-free hydrogenase

20. Contd • Problem: Hydrogenase, Ferredoxin and Nitrogenase is very sensitive to O₂ • Solution: [O₂] < 0.1% • Yield = Max H₂

21. Direct Biophotolysis

22. Indirect Biophotolysis • Definition: • Process to produce H₂ from water using microorganism (microalgae and cyanobacteria) by conversion of sunlight energy into chemical energy (H₂) though • Light dependent process • Light independent process

23. Reaction Equation • Biomass production by photosynthesis • Biomass concentration • Dark aerobic fermentation • Conversion of 2 mol of acetate into H₂

24. Role of Nitrogenase • This enzyme is found in the heterocysts of filamentous cyanobacteria • Responsible for nitrogen fixation • It reduce N₂ to NH₃ to produce hydrogen with consumption of reducing power and ATP 16ATP+16H₂ O+N₂ +10H⁺ +8e⁻ 16ADP+16Pi+2NH₄⁺+ H ₂

25. In N₂ fixing strains, the net H₂ production is the result of H₂ evolution by nitrogenase • H₂ consumption mainly catalyzed by the uptake hydrogenase.

26. Structure of Nitrogenase Nitrogenase consists of two part : • Dinitrogenase (MoFe Protein, encoded by the genes nifD and nifK, a and b respectively) • breaks apart the atoms of nitrogen • Dinitrogenase reductase (Fe Protein, encoded by nifH ) • transfer of electrons from the external electron donor (a ferredoxin or a flavodoxin) to the dinitrogenase

27. Role of Nitrogenase & Hydrogenase In Cyanobacterial Hydrogen Production

28. Limitation of Hydrogen

30. 1 • System for producing, storing, and delivering the Hydrogen gas • Cost hundreds of billions of dollars to build. • More expensive than a system based on liquid fuels such as gasoline or methanol

31. Hydrogen itself is hard to move around • Required to be stored as compressed gas • Stored in gas cylinders or spherical containers • 2 • Complex storage capability

32. Explosive range is a 13- to 79-percent concentration in air • Colorless and odorless and burns with a nearly invisible flame • Hydrogen mixes with air faster than does gasoline vapor (diffusion coefficient for hydrogen is 0.61 cm3/sec) • 3 • Highly Flammable

33. Rates of hydrogen produced by biological systems are unknown to fuel cell engineers • Amounts of H2required for practical applications, such as fuel cells, are unknown to biohydrogen researchers • Rates of hydrogen produced by the various biohydrogen systems are expressed in different units. • Difficult to assess and compare the rates and amounts of hydrogen synthesized by different biohydrogen technologies • 4 • Less information exchange between scientist & engineers