Monday, April 25, 2011

Challenges in commercialization of algal fuel

• Optimize stress conditions to obtain the highest possible yields of lipids in the cells because stress conditions can induce spontaneous mutation in cultivated strains.


• Simplify harvesting systems to utilize the separation technologies in existing industry such as food, biopharmaceutical, chemical and waste water treatment sectors.


• Utilize existing biodiesel production processes that requires a lipid material free of both water and free fatty acids


• Develop water tolerant downstream processes to avoid cost intensive drying


Tuesday, April 12, 2011

Algae oil content of some microorganisms



Microorganisms
Oil content (% dry wt)
Botryococcus braunii
 25–75
Cylindrotheca sp.
16–37
Nitzschia sp.
 45–47
Schizochytrium sp.
50–77

Monday, April 4, 2011

Bioconversions of lignocellulosic biomass: the points we cannot overlook

Pretreatment

• If you pretreat biomass at alkaline conditions, be sure to separate lignin before neutralization. Otherwise, the solublized lignin will be precipitated or re-deposited when pH drops.
• If you pretreat biomass at acidic conditions, be sure the temperature does not exceed 165 C. Otherwise, the lignin will condense and re-distribute through cell wall and become gel coat on the surface of pretreated fiber
• If you pretreat biomass with organosolvents, make sure to recycle/re-use the solvents.


Post-pretreatment
• If run detoxification, make sure the methods to be used with fundamental mechanisms. It is cheap and scalable.
• Recover by-products and easily and economically deal with the chemicals if any.

Enzymatic hydrolysis
• Know what biomass you are using and their sugar composition. Woody and non-woody biomass has different chemical (especially lignin and hemicelluloses) composition.
• Know the pretreatment methods you used. The modification of cell wall structure and chemical composition differ under different thermochemical pretreatments.
• Know what substrate the enzyme cocktail development has been based on. Alkaline and acidic pretreated biomass will end up different cocktail characteristics. The enzyme cocktail may need to be customized in terms of the specific pretreated biomass.


Process
• Avoid or reduce unit operations as much as possible
• Be as simple as possible for process configuration
• Use high solids if possible

Fermentation
• Use cheap nutrients if possible
• Ferment C6 and C5 sugars if possible

Friday, April 1, 2011

Fatty acid composition of microalgal oil

 
Fatty acid
Chain length: no. of double bonds
Oil composition (w/total lipid)
Palmitic acid
16:00
12–21
Palmitoleic acid
16:01
 55–57
Stearic acid
18:00
1–2
Oleic acid
18:01
58–60
Linoleic acid
18:02
4–20
Linolenic acid
18:03
14–30


(Meng et al., 2009).

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