Lecture 4+5 biorefinery ex. and ethanol production Flashcards Preview

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Flashcards in Lecture 4+5 biorefinery ex. and ethanol production Deck (21)
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1
Q

What is the project BioBUF?

A

Upgrading of renewable domestic raw materials to value-added bulk and fine chemicals for a biobased economy: technology development, systems integration and environmental impact assessment.

2
Q

What challenges are they addressing?

A
  • replacing fossil-based raw materials with biobased raw materials
  • smarter use of raw materials by developing a highly
    integrated biorefinery concept, including technology for using all parts of the raw material for simultaneous
    production of several bulk and fine chemicals
  • careful analyses of the environmental impact and the economic performance of suggested processes
3
Q

What can adipic acid be used for?

A

As a platform chemical used for production of

nylon and a broad range of chemicals

4
Q

What is GROT?

A

The waste from the forestry industry (grenar och toppar)

5
Q

How can GROT be used?

A

It can be converted into lignin, hemicellulose and carbohydrates. Lignin can be converted to aromatic compounds which can create valuable biochemicals. Sugars from GROT can possibly also be used to create adipic acid.

6
Q

Whats the main substrates in 1st generation bioethanol production?

A

sugars and starch

7
Q

What is Dry milling VHG SSF?

A

A typical industrial process for fuel ethanol production. Creates Ethanol and DDGS (=Dry matter/cereal bi-product from the process, also includes yeast and enzymes).
VHG = Very high gravity
SSF= simultaneous saccharification and fermentation

8
Q

Are cells metabolic active if they do not grow?

A

Usually no. If they do not grow they are generally not metabolically active. E.g. If yeast stop growing ethanol production decreases a lot

9
Q

What are the substrates of 2nd generation ethanol production derived from?

A

Cellulose, hemicellulose and lignin

10
Q

How does the typical 2nd generation ethanol production look like?

A

Enzymatic hydrolysis to degrade the polymers to create fermentable sugars-> fermentation -> product

11
Q

What challenges are there to high solid loadings? e.g. using lignocellulose

A

Separation/enzymatic hydrolysis costs
water economy (it holds a lot of water)
Creates a viscous media - mixing problems
higher levels of inhibitory compounds

12
Q

What strategies can you use to get a more robust 2nd generation process?

A
  • Pretreatment for detoxification (=less inhibitors)
  • More cells and nutrients (yeast extract)
  • Evolve the strain to perform better
  • Optimization of the process schemes
13
Q

What is a hydrolysate?

A

Any product formed from hydrolysis

14
Q

How can you use evolutionary engineering?

A

Example: improve hydrolysate conversion and inhibitor tolerance. Can be done by adapting the yeast to e.g. lignocellulosic hydrolysates during propagation to improve their performance.

15
Q

What’s the multi-feed SSCF process?

A

Pretreated wheat straw (or similar) is divided into liquid and solid fractions. Yeast cultivation on the liquid fraction then cells feed to SSCF. In the fed-batch SSCF enzymes and the solid/dry feed are added. This process improves mixing and reduces inhibition!

16
Q

What does SSCF stand for?

A

simultaneous saccharification and co-fermentation

17
Q

Which strain improvements are generally best for robustness?

A

Reduce: uptake and damage
Enhance: Excretion, repair and conversion (detoxification)

18
Q

Why is the increased expression of Glutathion good?

A

It is oxidative (damage repair), xenobiotic (detoxification) and redox (buffering). So it can tolerate higher ethanol conc.

19
Q

Why is it good to enhance the phenolic compound conversion?

A

Phenolic compounds from e.g. lignin, can be toxic to the cell. But they can also be used as products that are very wanted like antioxidants, fine chemicals - acids, aldehydes, alcohols. The ability to convert = better = detoxification.

20
Q

Which enzymes can be good to over-express in order to detoxify the cell?

A

Aldehyde dehydrogenase, decarboxylase and deacetylase

21
Q

Why can it be favourable for the cells to have a high amount of sphingolipids in their cell membrane?

A

It decreases the uptake of acetic acid (acids overall) which is good! The membrane becomes more thick and condensed.