Versions Compared

Old Version 14

changes.mady.by.user Unknown User (mollyb@mit.edu)

Saved on

compared with

New Version 15

changes.mady.by.user Unknown User (mbuss@mit.edu)

Saved on

Key

  • This line was added.
  • This line was removed.
  • Formatting was changed.
  • One approach: using Caldicellulosiruptor saccharolyticus
    • Gram-positive anaerobic bacterium that ferments a broad spectrum of mono-, di- and polysaccharides to mainly acetate, CO2 and hydrogen
    • hydrogen yields approaching the theoretical limit for dark fermentation of 4 mol hydrogen per mol hexose
    • organism has proven itself to be an excellent candidate for biological hydrogen production
    • ability to produce thermostable cellulolytic and xylanolytic enzymes, to grow on complex lignocellulosic carbon sources, and to co-metabolize a wide spectrum of monosaccharides including both pentose and hexose sugars
    • factors to consider: hydrolytic capability, sugar metabolism, hydrogen formation, mechanisms involved in hydrogen inhibition, regulation of the redox and carbon metabolism
    • challenges/drawbacks:
      • growth medium
      • growth temperature
  • Coupling hydrogen production with other processes 
    • formate production to fuel hydrogen production (iGEM Tokyo 2012)
    • using hydrogen production in a bacteria in conjunction with another bacteria or system that would allow cheaper or more efficient production of another useful molecule
      • hydrogen produced in conjunction with an electroconductive bacteria (Geobacter - Nick works with it in his lab) to immediately produce electricity
  • Modify the endogenous activator of the operon and up-regulate it to increase hydrogen production
  • Using a new gas separation process to remove/purify the hydrogen
  • concept of "consolidated bioprocessing"
    • one bacteria is able to produce cellulase, hydrolyze cellulose, and ferment in one step
    • This increases efficiency decreases total cost, and removes the requirement for pre-treating the biomass.
    • Putting multiple hydrogen production pathways in each bacterium
      • hydrogenase, plus formic acid, plus etc.
  • Using a moderate thermophile
    • more versatility
    • T. thermosaccharolyticum

 

link to articlesummary/important points
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3003633/

background information about Caldicellulosiruptor saccharolyticus

http://2010.igem.org/Team:ULB-Brussels/H2goal: increase the H2 production by modifying the carbon flow through the pathway of the mixed acid fermentation
http://2012.igem.org/Team:UT-Tokyoformic acid
http://www.sciencedirect.com.ezproxyberklee.flo.org/science/article/pii/S0360319906002205Integration of biohydrogen fermentation and gas separation processes to recover and enrich hydrogen
http://www.sciencedirect.com.ezproxyberklee.flo.org/science/article/pii/S0960852413006093Consolidated bioprocessing of untreated switchgrass to hydrogen by the extreme thermophile Caldicellulosiruptor saccharolyticus DSM 8903
http://www.biotechnologyforbiofuels.com/content/7/1/82Single-step bioconversion of lignocellulose to hydrogen using novel moderately thermophilic bacteriahttp://www.sciencedirect.com.ezproxyberklee.flo.org/science/article/pii/S0141022901003945
  Bioreacters