Flashcards in Microbial fermentation Deck (25):
Fermentation is ...?
Anaerobic digestion of substrates by bacteria & other microorganisms
Fermentative digestion enzymes are ___ in origin
Difference between fermentative & glandular digestion
Fermentative = SLOWER
Requirements for proper fermentation?
Temp = 37 degrees
Suitable substrate (CHO)
Indigestible material removed
Rate of removal = regeneration time of favourable microbes
VFAs removed or buffered
Major food sources for fermentation for large herbivores?
Forages/foliage of plants
Glue cellulose together?
Hemicellulose, lignin, pectin
CHO digestion involves which 3 plant CHOs?
Insoluble structural polysaccharides (cellulose, hemicellulose)
Soluble structural polysaccharides (gels - pectins)
Storage mono-, oligo-, polysaccharides (starch)
Function of the rumen?
Large, anaerobic fermentation vat
Soluble products mostly absorbed thru wall
Material leaving RR = food residues, bacteria, protozoa, (+soluble fermentation end products)
Fermentation microbes are mainly?
At least 28 important spp
A bit about fungi...?
Survive completely on ingested feed
Able to digest cellulose, starch etc
1st organism to attack & start digesting structural plant components
Not numerous, but take 1st bite
A bit on rumen bacteria..?
Most are strict anaerobes
10^10 bacteria/g ingesta
Synthesis microbial protein
Wide range >200 spp.
Pop. needs time to adapt to change in diet
Rate of bacterial population depends on?
Bacterial turnover time
Limited by cellulose digestion
Limited by starch storage by protozoa
Bacterial growth requires...?
N for protein synthesis (ie ammonia, AAs, urea or peptides)
Other micronutrients (sulphur)
Rumen bacteria & substrates are...? Give egs
Widely adapted (Lactobacilli/butyrivibrio)
Digest cellulose & hemicellulose (Ruminococcus)
Digest starch (streptococcus bovis)
Properties of methanogens...?
CH4 (methane) producing archea
Similar to bacteria
Produce methane as end product of feed in rumen
Example of methanogens?
Much larger than bacteria
Fewer in number
Increase with [starch]
Feed on bacteria
removal of protozoa -> increase bacteria -> increase bacterial protein-N -> decrease ruminal [NH3]
Most important protozoa?
2 families of protozoa & apperance?
Holotrich - 'hairy' covered by cilia
Entodiniomorphid - 'tufted' most of body naked except tufts/patches of cilia
Use starch & sugars
Associated with feed particles
Do not readily pass from rumen
Fermentation end products of holotrichs?
Ingest starch, plant material, bacteria
Increase in no. when animal eats grain diet
Cell membrane NOT cell wall
~10^6/g ruminal contents (sheep/cattle)
Important in maintaining balanced ecosystem
Provide energy for ruminants