Thursday, February 26, 2009
Tuesday, February 24, 2009
Monday, February 23, 2009
1. Different chemical components are analyzed by different methods and instrument, which cause the errors
2. For sugar analysis, each sugar has different optimal post-hydrolysis conditions, which cause both under and over hydrolysis of the sugars
3. Klason lignin includes some ash and proteins, which are accounted for twice
4. Uronic acid and acid lignin should be included when doing mass balance.
5. The standard solution composition should be as close as possible the real samples
Thursday, February 19, 2009
- Furfural is metabolized by S. cerevisae under aerobic, oxygen-limited, and anareobic conditions to furfural alcohol.
–Furfural reduce the specific growth rate, the cell-mass yield on ATP, the volumetric, and specific ethanol production
–NADH-dependent yeast alcohol dehydrogenase (ADH) is believe to be responsible for furfural reduction.
–Under anaerobic conditions, glycerol is normally produced to regenerate excess NADH formed in biosynthesis. Glycerol production reduction during furfural reduction suggests that furfural reduction regenerates NAD+.
–Elevated concentrations of acetaldehyde excreted in the beginning of the fermentation, which was suggested to be due to a decreased NADH concentration in the cell during furfural reduction.
–Furfural inhibition of glycolytic enzymes in vitro and the direct inhibition of ADH might have contributed to acetaldehyde excretion.
–Intracellular acetaldehyde acumination suggested to be the reason for lag-phase in growth in the presence of furfural.
»i) furfural reduction to furfural alcohol by NADH dependent dehydrogenases had a higher priority than reduction of dihydroxyacetone phosphate to glycerol
»ii) furfural caused inactivation of cell replication.
Tuesday, February 17, 2009
Uncoupling and intracellular anion acumination
–The drop in intracellular pH resulting from inflow of weak acids is neutralized by the action of plasma membrane ATPase, which pumps protons out of the cell at the expense of ATP hydrolysis. At high acid concentration, the proton pumping capacity of the cell is exhausted, resulting depletion of the ATP content, dissipation of the proton motive force, and acidification of the cytoplasm.
–However, the anionic forms of acetic, formic acid, are lipophobic and do not traverse the plasma membrane in both dissociated and undissociated form, causing a high rate of proton impart. The extent of intracellular anion accumination will be a function of the pH gradient over the plasma membrane.
Monday, February 16, 2009
- Barrier to cellulase enzymes
– limit the efficacy of hydrolysis
- Adsorb cellulases
–Increase enzyme loading and therefore the cost
- Phenloc compounds partition into biological membrances cause loss of integrity, therefore affecting their ability to serve selective barriers and enzyme matrices.
Less heavily substituted phenolics are the most inhibitory compounds
Sunday, February 15, 2009
- this industry is the largest handler of forest residues (lignocellusics)
- $Millions investment has been completed in infrastructure, which will allow to save ~ 35% of capital cost versus a greenfield plant and utilize the boiler house, generators, control rooms, pipe bridges, water and effluent stations, warehouses, woodyards, wood procurement, storage tanks etc
- Hundreds of highly trained technical professionals are available for cellulosic biorefineries
- Co-production and process integration reduce allocated production cost for both pulp mill and biorefinery plant
- Bioethanol adds additional revenue to pulp and paper mills
There, when we borrow the ideas from paper industry to treat biomass , somehow we should not turn our attention away from this industry. More we can take advantge of them.
Thursday, February 12, 2009
Wednesday, February 11, 2009
I feel that it is very wise for both partners to make such a decision at an early stage in the project’s development and no significant costs have been incurred. They are serious about cellulosic biorefining.
My question is: what will happen if they continue to proceed the project with the government funding, or with misleading information? What about other players?
It is great lesson for us to learn from this wise decision.
Tuesday, February 10, 2009
For biofeuls and biochemicals industry, it is still uncertain when the great potential become reality. To use biomass as feedstocks, the utilization of hemicelluloses is the key because it accounts 20-28% of the chemical components in biomass and will have significant impact on the production cost. However the available cost effective technology for commercialization is not ready yet: the scalable microorganisms to ferment C5 sugars under toxic environment, the process to achieve high sugar recovery yield from biomass….
So it is the time for scientist and engineers to get in. It is also great time for investors to jump in if the opportunity has a solid fundamental support. Certainly, a detailed and solid technical evaluation before jumping in is very critical.
Monday, February 9, 2009
Friday, February 6, 2009
- Fatty acids
- Monoterpenes (turpentine)
- Phenolics (Gallic acid, vanillin, Stilbenes, Flavonoids, Lignans)
Extractive components are “small” molecules that can be extracted with a solvent from wood, bark, or foliage.
-Generally, extractives are present in small amounts.
-Extractives vary tremendously within species, between species, and within trees.
-There are thousands of different extractives present in wood.
Thursday, February 5, 2009
Wednesday, February 4, 2009
"The chemical industry, however, is a different animal when it comes to looking for CSOs. Aside from the required tree hugger and company-conscience roles, sustainability leaders of chemical companies need to be technically and financially savvy, understand how the industry operates from top to bottom, and be a long-term strategic thinker."
Actually, there is a great need of real professionals who has solid technical background and experience in these areas. However, we can not build up the Rome city overnight. It takes time and need more patience... Otherwise, the fake experts will cause more problem than the fresh learners.
Monday, February 2, 2009
It has been found that the affinities of acetic acid and furfural (and HMF) are much higher than that of the sugars. The key parameters include activated carbon particle size (surface areas), the ratio of activated carbon to hydrolyzate, temperature, and adsorption time, etc.
The activated carbon can be packed into a column and the hydrolyzate will be pumped into the column. The residence time will be determined by the flow rate and the length of the column.
A inline IR or UV detector can be used to monitor the compounds in the eluent.
Sunday, February 1, 2009
Here is one of the research projects conducted at The BioEnergy Science Center.