Organic acids production copy

Generally, organic acids are produced commercially either by chemical synthesis or fermentation. ... All organic acids of tricarboxylic acid cycle can be produced in high yields in microbiological processes. Among fermentation processes, the production of organic acids is dominated by submerged fermentation.

1. Organic Acids Production
Acetic acid, Lactic Acid, Citric Acid

2. Acetic Acid
Production

3. Introduction
•Aceticacidisoneofthemostimportantorganicacids.
•Diluteaceticacid(~4%)isknownasvinegar(vin(wine)aigre(sour)=
sourwine).
•Microorganismsused:AcetobacteracetiorGluconobacteroxydans,
whichbelongtotheFamilyAcetobacteriaceae.

4. Mechanismofformation
•Rawmaterial:GlucoseorEthanol
•Conversionofethanoltoaceticacidisoxygenrequiringprocessand
henceknownasOxidativefermentation.
•Conversionofethanoltoaceticacidisanexothermicreaction.
•Aceticacidbacteriagenera:GluconobacterandAcetobacter.
•GluconobacteroxidisesethanoltoaceticacidwhereasAcetobacter
oxidizesethanoltoaceticacidandthenfinallytoCO
2andH
2O.
•StrainsofAcetobacteraregenerallyinvolvedinvinegarproduction.

5. Production
Slow Process Fast Process
Static Acetic acid
Fermentation
(Trickling method)
Tower Reactor
German Method
Wood Shavings
Charcoal
Alcohol Feed
Air
Time Consuming
Need a month to
complete fermentation
Fermentation time
reduced
from months to week
Production is10 times higher
Raw material: Ethanol or wine

6. Recovery
Filtration Decolourization

7. TypesofVinegar
1.DistilledWhiteVinegar
Madefromhighqualityethanol,doesnothaveanyaroma.
2.AppleCiderVinegar
Madefromfermentedapplejuiceorapplejuiceconcentrates.
3.WineVinegar
Madefromlowqualitywines(Redandwhite)byoxidativefermentation.
4.MaltVinegar
Madefromalcoholicandacetousfermentationofmaltstarchorcornstarch.
MaltstarchorCornstarchsfirsttreatedwithenzymestoreleasesugars.
Sugaristhenfermentedbyyeasttoethanol.Thisethanolisthenconvertedto
aceticacid.

8. Chemical Synthesis
Vinegar is produced by Carbonylationof methanol by Monsanto process
CH
3OH + CO CH
3COOH
D-Rhodium complex
180°C, 30-40 atmpressure

9. Lactic acid
Production

10. Introduction
•Lacticacidfermentationwasdiscoveredasearlyas1780byScheele,who
foundthatsouringofmilkisduetoformationoflacticacidbygroupof
bacteriacalledLactobacilli.
•Lacticacidproducingbacteriaarebroadlyclassifiedintotwogroups,based
onproductsformedfromglucose.
1.Homolacticfermenters
2.Heterolacticfermenters
HomolacticfermentersdissimilateglucosebyEMPpathwaytolacticacid.
TwomolesofATPsareproducedpermoleofglucoseutilized.
HeterolacticfermentersdissimilateglucosebyPentosePhosphatePathwayto
equimolarconcentrationofthreeendproductsviz.lacticacid,ethanoland
CO
2.OnlyonemoleofATPisproducedpermoleofglucoseutilized.

12. Microorganismsused
•Forindustrialproduction:Lactobacillusdelbrueckiiwhichutilize
glucose
•Lactobacillusbulgaricuswhichutilizelactose
•Lactobacilluspentosuswhichutilizepentoseofsulfitewasteliquor

13. ProductionandRecovery
ProductionMedia
•10-15%glucose
•10%CalciumCarbonate
•Nitrogenoussalts
•Calciumsaltconvertsthelacticacidproducedduringfermentationtocalciumlactate.
•Highsugarconcentrationnotusedasitcrystallizecalciumlactateandslowdownthefermentationprocess.
Fermenter
•20,000-100,000Liters
•Anaerobically
•pH5-6
•Lactobacillusdelbrueckii
•5-6days

14. •Attheendoffermentation,fermentationbrothisheated.
•Calciumlactateproducedduringfermentationisfilteredand
concentratedtoallowthecalciumlactatetocrystalize.
•Calciumisfinallyremovedascalciumsulphatebyadditionof
sulphuricacid.
•Lacticacidisthenrecrystallizedandused.
•Streptococcuslactis:produceonlylacticacid.
•Leuconostocmesenteroides: produce lactic acid, ethanol, CO
2

15. Citric Acid
Production

16. Introduction
•Citricacidisweakorganicacidalsoknownaslemonsalt,foundsin
fruitsandberries.
•IN1922Molliarddiscoveredthatcitricacidaccumulatesinculturesof
AspergillusNigerundersubmergedfermentationprocessandunder
conditionsofnutrientdeficiency.

17. Commercial Production of Citric Acid
•AspergillusNigermostcommonlyused.
•YeaststrainssuchasCandidaguilliermondiiandC.lipolyticaarealsoused
forproductionofcitricacidinsmallerquantities.
•Therearethreewellknownmethodsforcommercialproductionofcitric
acid:
1.TheJapanesekojicacidprocess,inwhichspecialstrainsofA.nigerare
used.
2.Theliquidsurfaceculturefermentation,inwhichA.nigerfloatsonthe
surfaceofculturemedium.
3.Thesubmergedfermentationprocess,inwhichfungalmyceliumgrows
throughoutthemediuminadeeptank.

18. •A.Nigerisused
•InWheatbranmedium,pH4-5
•After5-8daysoffermentation,
kojiisharvestedandplacedon
percolatorsandcitricacidis
harvestedusingwater
Spreadintray Windrowsonfloor
Wheat bran medium
1. Japanese kojicacid process
Percolator

19. 2. Liquid surface culture fermentation
Spores germinate within 24 hours
White mycelium cover the surface of medium
Inoculated medium
pH 5-6
Dispersed in Shallow pans of
Aluminum or Stainless steel
•Humidified Air then dry air
•5-6 days
•After 9 days of inoculation, sugar concentration reduced from 20% to 2%
•At the end of fermentation, spent medium is drained off and used for citric acid recovery.
Raw material: Sugar beet molasses

20. 3. Submerged fermentation process
•Low investment and operating cost
•80% of world production of citric
acid
•Less sensitive to changes in
composition of media
•Copper and Iron play important
role
•Copper ion inhibit citric acid
enzyme aconitase(convert citrate
to isocitrate)
•Yield is 84%-85% when beet
molasses is used, 82% when n-
alkane is used as substrate.
•Invert molasses
•Copper & Iron
•0.01-0.3% KH
2PO
4
•0.25% MgSO
4.
2H
2O
•pH 3.5
•Aeration 0.5-1.5 v/v per minute

21. Citric acid production by A. Niger

22. Recovery
•Precipitationofoxalicacid(antifoamagentused)intheformofcalciumoxalateat
lowpH.
•CitrateisprecipitatedasCalciumcitratebyadditionofhotneutral(pH7.2,70-
90°Ctemperature)aqueoussolutionofCa(OH)
2(theprocessknownasliming).
•Calciumcitrateisthenfilteredusingrotaryfiltertoformfiltercake.
•Filtercakeistreatedwithdilutesulphuricacidtoprecipitatecalciumascalcium
sulphateleavingthecitricacidinthesolution.
•Furtherpurifiedusingcarbongranulecolumn.
•Demineralizedbyionexchangecolumn.
•Purifiedsolutionisevaporatedincirculatingevaporatorandcrystalized.
•Crystalsarecollectedbycentrifugation,markedeitheranhydrousorinits
monohydrateformorsodiumsalt.

23. Recovery
Precipitation of oxalic acid
Calcium citrate (Liming)
Calcium sulphate
Purification
Demineralization
Evaporation
Centrifugation
Ca(OH)
2
Filtration, H
2SO
4
Carbon granule column
Ion exchange column
Circulating evaporator
Anhydrous or monohydrate or sodium salt of citric acid