Heaphy 10 biotechnology

Question 1

Microbial Biotechnology uses:

x5

Answer 1

• biomass production,
• fermentation, often central to microbial biotech
• secondary metabolism
• Mining (not discussed)
• ‘genetic engineering’.

Question 2

FUEL

Answer 2

• Petrol: finite, trade balance, political.
• Microbial production of fuels:
• e.g. ethanol; Brazil, ‘gasohol’, fermentation of renewable sugar cane
• yeasts still used commercially: despite benefits, reduced pollution, expensive => distil to recover pure ethanol reduces net energy gain.

Question 3

Thermoanaerobacter ethanolicus:

Answer 3

thermophilic ferments above boiling point of ethanol, allows continuous distillation.
• Commercial substrates, corn sugar & plant starches,

Question 4

Clostridium spp:

Answer 4

cellulose (wood) => fermentable sugars.

Question 5

Oil seed rape, algae to

Answer 5

‘Diesel’

Not C neutral & not as cheap as petrol

Question 6

• Hydrogen:

Answer 6

photosynthetic algae / bacteria grown in continuously renewable cultures. (Water is the by product!)BIOMASS PRODUCTION SINGLE CELL PROTEIN

Question 7

• Single cell protein SCP

Answer 7

high-yield protein source =>animal feed early 1960s.
• BP: SCP high vitamin content from yeast => long-chain hydrocarbons in crude petroleum, no longer economic in west.
• still commercial production of yeast SCP using natural gas as substrate

Question 8

Methylophilus methylotrophus

Answer 8

1960s: single carbon compounds, e.g. methane.
• Bacterium grown in pressurised fermenters: continuously harvested, dried, sold as pellets => animal feed.
• Not suitable for human consumption high content (~10%) of nucleic acid, (allergic reactions, kidney stones, etc.).

Question 9

Fusarium venenatum

Answer 9

filamentous fungus

(‘Quorn’), lower nucleic acid content, flavoured for human food.

Question 10

Fusarium venenatum

advantages:

Answer 10

• isolated from soil in Buckinghamshire.
• Microscopic fungus.
• Healthy meat substitute: 12% protein, lacks animal fat & cholesterol.
• Fibrous structure confers gastrointestinal advantages & may help cut cholesterol in bloodstream.
• Substitute fat in dairy products.
• Fibre in cereals.
• Grows on glucose, on any cheap abundant vegetable, anywhere in world.
• Animal feed w/ leftovers

Question 11

QUORN

production process:

Answer 11

• two vertical cylinders, ~50 m high
• connected to form a continuous loop w/ vol ~150m3.
• Culture broth 95% vegetable derived glucose
• continuous process total vessel biomass ~2,250 kg.
• Sparge bar, injects air & ammonia – an air lift culture vessel.
• Broth continually circulates between the two.
• Complete vessels contain ~230 tons of broth.
• 30 tons of the cultured broth are removed per hour.
• Standard production rate of ~7 hydrated metric tons per 24 hour cycle.

Question 12

FERMENTAION:

Answer 12

Reductant & oxidant, redox couple, are both organic

Question 13

FERMENTAION: E.G.

Answer 13

Pyruvate metabolism without oxygen, form of anaerobic respiration.

Question 14

BEER equation of fermentation:

Glucose is..
Acetaldehyde is..

Answer 14

C6H12O6 +2Pi+ 2ADP> 2C02+2C2H5OH +2ATP+2H20.

Glucose is the reductant, acetaldehyde the oxidant.

Question 15

Beer fermentation process:

Answer 15

• Beer & ale malt-based; traditional ales from barley malt
• Barley germinate for week
• crushed to release amylase (degrades starch.)
• Converts complex carbohydrates => sugars for fermentation ( CO2 gives beer a ‘head’) hops provide flavour & sepsis control.

Question 16

Wines:

Answer 16

grape juice; some vineyards still use ‘wild’ yeasts

• Modern, large-scale production uses ‘improved’ strains.

Question 17

alcoholic content

Answer 17

beer & wine, alcoholic content limited by tolerance of yeasts to alcohol (beers ~5%, wines 10-15%)
• spirits (~40% alcohol) made by distillation.

Question 18

Saccharomyces cerevisiae: :

Answer 18

bread, ferments sugars derived from starches in wheat => ethanol & CO2, expelled during baking & CO2 trapped to give lightness & texture to bread

Question 19

Streptococcus species S. cremoris,

Answer 19

MILK
ferment and acidify, separates into curds (proteins+fat) & whey(liquid portion). Curds cultured with secondary microbial species.

Question 20

S. lactis

Answer 20

MILK
• Lactic acid bacteria convert milk sugar lactose => lactic acid, different characteristic flavours & smells due to minor fermentation products. Pasteurisation

Question 21

Characteristic flavours& appearances depend on:

Answer 21

starter culture organisms, culture times and conditions

Question 22

Organisms used in secondary fermentation:
cheese
camembert
holes in cheese

Answer 22

Penicillium species for pungent cheeses
• e.g. P. candidium for Stilton, P. camemberti for Camembert)
• Lactobacillus helveticus, and Propionibacterium freundenreichii holes in cheese

Question 23

Lactobacillus bulgaricus

Answer 23

YOGURT
Heat milk, take precipitates, ferment at 40°C w/ bacteria => produces acetaldehyde & lactic acid, gives yoghurt characteristic tart taste, bacteria alive when yoghurt eaten.

Question 24

SOY SAUCE

Answer 24

mixture of soy beans & wheat with fungus Aspergillus oryzae => amylase &proteinases,
- degrade plant tissues &storage compounds releasing fermentable sugars.
• micro-organisms associated with soy beans then use sugars sequentially i.e. microbial populations change over time:
· lactic acid bacteria e.g. Pediococcus soyae convert lactose to lactic acid, prevents spoilage. yeasts e.g. Zygosaccharomyces soyae ferment other sugars to produce alcohol and flavour

Question 25

Saccharomyces cerevisiae

Answer 25

VINEGAR STAGE 1

· fermentation of sugar in fruits, vegetables, cereals => ethanol

Question 26

Acetobacter species

Answer 26

VINEGAR STAGE 2

· conversion of ethanol to acetic acid by Acetobacter species (oxidative metabolism requiring high pressure forced air)

Question 27

Amino acids made using micro-organisms:

Answer 27

Corynebacterium genus

Question 28

Corynebacterium glutamicum:

Answer 28

glutamic acid, flavour enhancer monosodium glutamate, also makes lysine, essential nutritional supplement for farm animals

Question 29

Aspergillus niger:

Answer 29

molasses => citric acid, food additive

• microbes produce biologically important L-isomers, chemical synthesis gives L- and D-isomers.

Question 30

• industrial enzymes made from microbial cultures:

Answer 30

• proteases: laundry (spot removal), leather making, meat tenderising, textiles
• amylase : baking, brewing, chocolate, paper, laundry
• veggy rennin - dairy industry (curdles milk)
• Microbial transformation of steroids, e.g. cortisone anti-inflammatory, by Rhizopus stolonifer, much cheaper than chemical synthesis (40 p/gram cf. >£150/gram).
• Aspergillus terreus : itaconic acid, used as plastics resin, made from citric acid

Question 31

SECONDARY METABOLITES

Answer 31

not required for growth

Question 32

Antimicrobial compounds:

Answer 32

antibiotics by micro-organisms, industrial turn-over of $ billions per year worldwide.

Question 33

• Penicillium:

Answer 33

penicillin (fungus), in fermentation run of 7-10 days, biomass increases rapidly for 5+ days, but penicillin production only begins when nutritional starvation occurs.

Question 34

examples of bacteria used in antibiotics

Answer 34

species of Streptomyces, e.g. chloramphenicol by S. venezuelae, erythromycin by S. erythrae, streptomycin by S. griseus.