K.K Lecture 5&6

Question 1

Why develop Mycoprotein (aka fungal protein)?

Answer 1

• world population increasing
• animal protein is expensive
• diseases are caused due to lack of protein

Question 2

Why should we develop a novel food?

Answer 2

• it has high nutritional value
• acceptable to public
• it uses cheap raw materials

Question 3

Why should we use filamentous fungi?

Answer 3

• it is well studied
• it has low nucleic acid content
• it is fibrous
• it is safe to use

Question 4

What are the materials and fungi used in single cell protein (SCP) production?

Answer 4

look at slide 8

Question 5

Mycoprotein screening

Answer 5

• screening : Ranks, Hovis McDougal (RHM)
• initially looked at penicillium spp.
• 1968-1971 : 3000 soil isolates sample tested
• isolate A3/5 : this was isolated on day 3 of screening, 3 miles from the lab in Buckinghamshire, England

Question 6

Fusarium gramineraum

Answer 6

• growth rate: MGT 3.5 hours
• optimum temp: 30 degrees C
• optimum pH: 4.5-8.0
• the yield is 0.54 on glucose
• you can grow on glucose and get 54g fungus wet weight and 45% of the 54g is protein which is most likely edible

Question 7

Mycoprotein fermentation process

Answer 7

• continuous cell cycle
• essential for productivity
• cycles : 3000 hours
• air lift fermenter
• keep cultures in exponential phase as it will actively grow
• use starch as food stock

Question 8

Why was starch used in the mycoprotein fermentation process?

Answer 8

because it is the cheapest raw material that the farmer was spraying on the field so the fungus was selected on starch

Question 9

What was the problem with the starch?

Answer 9

the RNA content was too high and eating food with excessive RNA content will result in uric acid. the RNA gets broken down in the liver to uric acid

Question 10

How can you reduce the RNA content?

Answer 10

• temperature shock (30 mins at 64 degrees celsius)
• RNA reduces from 10-2%
• this will increase the protein

Question 11

Airlift fermenter

Answer 11

look at slide 12

Question 12

What is the problem with the fermentation of mycoprotein and how can we control it?

Answer 12

• the appearance of highly branched variant after 400 hours arises spontaneously
• this affects the texture of the final product
• can control it by limiting nutrients, pH and selection

Question 13

How can we harvest mycoprotein?

Answer 13

by using fungal biomes which is easy to harvest

Question 14

Was the safety of mycoprotein checked? if so how how was it done?

Answer 14

• yes it was, it was done by doing animal and human trials
• there was a range of animal species and 2500 humans
• there was no mycotoxins present

Question 15

Food formulations of mycoprotein

Answer 15

• the food value is equivalent to milk protein
• it has 75% food value of steak
• there is low fat and no cholesterol
• Mycoprotein had a fibrous texture like chewing meat or a ‘mouth-feel’

Question 16

Quorn

Answer 16

• launched in 1985
• low fat, it is a healthy option
• it took 15-20 years to get to the market

Question 17

What factors affect the production of fungal enzymes?

Answer 17

• fungus
• strain selection
• fermentation process

Question 18

What factors does the fungus need to be to be used for production?

Answer 18

• needs to be non-pathogenic
• non-toxin producer
• needs to be generally regarded as safe (GRAS)

Question 19

What factors does the strain selection need to be to be used for production?

Answer 19

• needs to enrich and screen for high producers
• reverse catabolite repression - need an inducer

Question 20

What factors does the fermentation process need to be to be used for production?

Answer 20

• when it’s in a solid state it can cause problems
• the batch needs to be controllable
• the medium needs to be cheap and abundant (C-source: barley, corn. N-source: yeast extract)
• yield must be high
• location of enzyme: is it intra or extra-cellular?

Question 21

Why use fungi?

Answer 21

look at slide 3 (lecture 6)
- fungi need a wide range of enzymes to grow in the environment

Question 22

What are the fungal enzymes?

Answer 22

look at slide 6 (lecture 6)

Question 23

Application of enzymes in fruit juice maceration?

Answer 23

• pectinases, cellulases, hemicelluloses used to extract and purify fruit and vegetable juices
• alpha-amylases and amyloglucosidase remove haze from apple juices (to get clear and not cloudy apple juice)..
• pectinases ease peeling of citrus fruits.

Question 24

Tanning industry

Answer 24

• production of leather
• proteases and lipases from Aspergillus species to degrade keratin of hair in hides

Question 24

Application of enzymes in bioethanol and biodiesel?

Answer 24

• cellulase to convert cellulose and lignocellulose to ferment ethanol, producing bioethanol
• lipases are used to process oils from rapeseed and animal/vegetable fats to give fatty esters for use as biodiesel

Question 25

Biofuel production

Answer 25

look at slide 10 (lecture 6)

Question 26

Effluent and waste treatment

Answer 26

• poultry industry - 5% weight of chicken-feathers
• feathers are degraded by proteases and used as a protein source

Question 27

Catalase 1.11.1.6.
Systemic name H2O2

Answer 27

• 2H2O2 = 2 H2O + O2
• source: Aspergillus niger
• applications: cold sterilisation of milk, and cheese. deactivate hydrogen peroxide in bleaching of hair/textiles

Question 28

Glucose Oxidase1.1.3.4 beta-D-Glucose: O2 oxide-reductase
(breaks down glucose in the presence of oxygen to produce gluconicacid)

Answer 28

• D-Glucose + O2 + H2O = D-gluconic acid + H2O2
• source: Penicillium notatum
• applications: de-oxygenation of fruit juices, soft drinks, wines. removal of glucose from dried foods - coffee, soups. to measure glucose in urine (Clinistix)

Question 29

Carbohydrate hydrolysing enzymes

Answer 29

alpha-amylase 3.2.1.1 alpha-1,4-glucan 4- glucanohydrolase
- starch= glucose + maltose + oligosaccharides
- source: saliva, Aspergillus species or bacteria
- applications: improve texture& appearance of bread. malting barley for brewing. preparation of syrups for chocolate manufacture.
beta-amylase 3.2.1.2 alpha 1,4-glucan maltohydrolase
- starch= maltose + dextrin (not really fermentable)
- applications: maltose production from starch

Question 30

Manufacture of high fructose corn syrup

Answer 30

look at slide 16 (lecture 6)

Question 31

Cellulase 3.2.1.4 beta-1,4,-glucan glucanohydrolase

Answer 31

• cellulose = glucose + oligosaccharides + polysaccharides
• source: plant degrading fungi
• applications: oil extraction from vegetables. starch recovery from fibrous waste. yeast protoplast formation

Question 32

Invertase 3.2.1.26 beta-D-fructofuranoside fructohydrolase
(break down of solid block of sugar to fructose and glucose)

Answer 32

• sucrose = glucose + fructose
• source: yeasts + moulds
• applications: prevention of crystal formation in jams
• preparation of fructose syrup in the confectionery industry

Question 33

Pectinase 3.2.2.15 Polygalacturonide

Answer 33

• Pectin = galacturonic acid + other sugars
• source: fungi
• applications: oils from citrus fruits. fermentation of coffee beans. clarification of wine must and fruit jucies

Question 34

What are the advantages of fungal enzymes?

Answer 34

• they are specific
• they are safe to use
• they have low environmental impact
• they have a variable production
• it is easy to isolate fungi from environment