bioconversion of whey

2. WHAT IS WHEY ?
Whey is the portion of milk remaining after
casein and fat are formed into cheese curd ,
usually by acid , heat or rennet .
OR
It is the watery part of milk remaining after
separation of the curd , which results from the
coagulation of milk proteins by acid or
proteolytic enzymes. It is the by product of
cheese and casein manufacture.

3. •Whey is a rich source of minerals , calcium,
phosphorus , potassium , sodium, copper
and iron .
•These minerals have good digestive
qualities.
•It is also a very good source of vitamins of
the B-complex group , riboflavin and
pantothenic acid.(Nickerson 1974)

4. Whey is generated at the rate of about 9kg for
every 1 kg of cheese or 6 kg for every 1 kg of
cottage cheese (91% of the milk processed ).
1Kg of cheese 9 L of whey

6. Need of bioconversion :-
• Whey arising from cheese and casein manufacture has a BOD
of 50 g/l and COD of 70g/l. It is considered as a pollutant.
• 50% of 115 million tons of whey produced yearly disposed to
rivers and lakes.
• It must be treated prior to disposal.
• Bioconversion of whey has been used to produce saleable
products whilst reducing the organic load by greater than
75%.

7. “One hundred kilograms of whey are equivalent to
the sewage produced by 45 people (Jelen 1979).”

8. Products formed by bioconversion of
whey
• Ethanol
• Yeast biomass and bioproteins
• Methane
• Organic acids

9. 1.) Biomass :-
• MATERIALS AND METHODS :-
 MICROORGANISMS:-
• Yeast strains :-
1. Trichosporon pullulans
2. Candida curvata
3. Cryptococcus podzolicus
4. Bullera oryza
5. Cryptococcus laurentii
6. Cryptococcus flavus
(Source:- www.conference khuisf.ac.in)

10.  Types of whey used as substrates :-
• Preserved whey by freezing until working or culturing them in
order to prevent lactose hydrolysis.
 Media for screening :-
• The initial pH of the medium – 4.5- 5.5 and sterilized by the
autoclaving (121degree Celsius for 15 min) .
• Medium is decanted to remove precipitated protein , dispensed
in flasks and then reautoclaved.
 Culture conditions:-
• Growth is carried out at 28 degree Celsius under shaking
conditions for 5 days.

11. Inoculums:-
• The inoculums are prepared from 2-3 days old
cultures.
• The organisms from a test tube slope are
suspended in 5 ml sterile distilled water and
then 1 ml suspension is directly into in the
Erlenmeyer flasks containing 50 ml medium.

12. Biomass yield :-
Clarified Whey
(paneer , cheese
,chana, etc.)
Supplementation
with nutrients,
buffering and
emulsifying agents.
Culturing of
microorganisms (up
to stationary phase)
Microbial biomass
Centrifugation
at 10,000 rpm /
10 min, 4
degree Celsius
Sterilisation

13. 2.) Methane:-
Method :- Anaerobic digestion treatment of whey
• In this method whey is initially hydrolysed and converted
to organic acids by acidogenic bacteria then the
degradation is followed by methanogenic bacteria.
• Advantage of the method :-
The production of methane as an energy source which
consist of 50- 70 % methane.

14. MATERIALS AND METHODS :-
• Whey :- store at cool temperature to avoid unwanted reaction.
• Inoculums :-
 It is the bioculture used for start up of reactor .
 For anaerobic reactor inoculums volume is around 10- 20 % of the total volume of
reactor.
• UAPB Reactor (upflow anaerobic packed bed ):-
 Two stage upflow packed bed reactor for treatment of whey is used .
 It consist of feed tank , two small digester ( reactor 1 and reactor 2 ) with
packaging material
, effluent collecting tank, gas collector etc.
 The flow rate of material inside the reactor was maintained by using height
difference between reactors and tank.

15. Steps :-
• Feed tank :- it is used as a reservoir of feed. It is a plastic container of 10 litre
volume , the ball valve is used to control flow rate.
• First reactor :-
 It is first anaerobic packed bed reactor contains small packing material.
 Reactor contains 10 litre volume of liquid in it
 Reactor is made by PVC pipe of diameter 160 & 700 mm in height .
 Both the end of pipe is closed by end caps of suitable diameter.
 Hydrolysis , acidogenesis and acetogenesis reactions are carried out in first
reactor
 It have three connections one at the bottom of reactor to connect it to feed tank
, second one at the middle of reactor as sample port to check pH and
temperature of reacting material.
• Second reactor :-
 It is used for growth of methanogenic bacteria .
 It has larger volume than methanogenic bacteria so get large population
methanogenic bacteria
 It has 20 litre volume plus 2 litre headspace for collection of gas.

16. • Sample port :-
Sample port connection is taken at middle of the each reactor
It is used to collect the sample for checking of different
parameter which effect on anaerobic digestion.
• Effluent tank :-
It is connected at the outlet second reactor for the collection of
effluent from reactor.
• Valves :-
Plastic ball valves are used for control flow between tank and
reactors.
Metal ball valve used for control gas flow.
Small size of plastic valves are used at sampled port.
• Gas collector :-
It is a plastic bottle of 500 ml volume and glass container of 2
litre .
It is used to measure gas volume by water displacement
principle.

17. UAPB Reactor (upflow anaerobic packed bed )

18. 3.) Ethanol :-
•Whey permeate from protein ultrafiltration is concentrated by reverse
osmosis to attain high lactose content.
•Lactose is fermented with some special strains of yeast.
•Once fermentation is completed the liquid (beer ) is separated and
moved to the distillation process to extract ethanol .
•The ethanol is then sent through the rectifier for dehydration and
then denatured .
•The effluent (stillage and spent yeast ) may be discharged to a
treatment system , digested for methane gas, sold as feed or further
processed into food, feed or other products.
Source:- www.rd.usda.gov

19. Yeast strain used :- Kluyveromyces marxianus
Efficient in fermenting lactose.

20. Carbery process:-
Whey Ultrafiltration
Reverse
osmosis
Whey
protein
concentrate
Substrate
fermentation
separationbeerdistillationDehydrationethanol
Yeast (propagation)
Yeast ( spent /
recycled)
stillage
Whey
cream
WPC Water
WPC:- WHEY PROTEIN CONCENTRATE

21. 4.) Lactic acid :-
When using whey ultrafiltrate as a substrate for lactic acid
fermentation , the medium must be supplemented with some
easily digestible nitrogen compounds.
The addition of yeast extract at a concentration of 1.5% (w/v) in
the whey filtrate , as a source of nitrogen / growth factors , give
the highest maximum productivity of lactic acid of 2.7g/l/h ( ROY
et al.)
The increase in lactic acid production is attributed to substances
such as amino acid , peptides , vitamins and several organic acids
including pyruvic and glyceric acid in yeast extract .

22. Processes used :-
•Batch process
•Continuous process
•Immobilized cell process
•Batch cultures produce higher quantity of lactic acid than in
continuous cultures.
•Continuous cultures on the other hand produce higher
productivity of lactic acid as well as the possibility to continue
the process for a longer period of time.

23. Organism Fermentation
mode
Lactic acid (g/l)
Lactobacillus
casei
Fed batch ,
coimmobilization
47
Lactobacillus
helveticus
Continuous , cell
recycle via
membrane
55
Lactobacillus
delbrueckii
Continuous , in
situ removal via
ion – exchange
resin
26.1
TABLE :- Different approaches of producing lactic acid
Source:- www. Lactic.angelfire.com

24. Process :-
•Type of reactor :- continuous stirred tank reactor
•Raw material :- whey
•Steps :-
 whey proteins are separated from the acid whey .
The lactose in the whey permeate is converted to lactic acid in
an un- aerated bioreactor by a strain of lactic acid bacteria
which does not require any further supplements , to lactate .
This method produces high concentration of biomass. High
and economic lactic acid productivities are also achieved by cell
recycling using an integrated cross- flow- filtration unit .
The product recovery is carried out by bipolar electrodialysis ,
converting lactate directly into the free acid .

25. Advantages:-
•Chemical Oxygen Demand (COD) reduction of waste water by
over 90 % with simultaneous recovery of useful products (L-
lactic acid, proteins, biomass).
•Production of the free lactic acid and recovery of the
neutralizing agent used in fermentation.
•Minimal amounts of supplements and additional chemicals.
•Economic production of lactic acid by the application of
environmentally sound technologies.
•High lactic acid productivities by cell recycle.

28.  www. Lactic.angelfire.com
 www.rd.usda.gov
 www.conference khuisf.ac.in
www.googleimages.com
nopr.niscair.res.in
Link.springer.com