1. Introduction
• In Dairy industries the processing of one litre of milk, yields about 8-10 litres of
waste water depending on the type of products manufactured.
• Whey is the major by-product, during the manufacture of cheese, paneer or casein
from milk.
• Proper disposal of whey is extremely important as it is considered as a pollutant due
to its high biological oxygen demand.
• Proper disposal of whey is extremely important as it is considered as a pollutant
due to its high biological oxygen demand
APPLICATION OF BIOTECHNOLOGY FOR DISPOSAL OF
WHEY AND DAIRY EFFLUENTS
2. Biotechnological Approaches in Treatment of Whey and Dairy Waste
• The strength of whey pollution in dairy waste is determined by two parameters
1) Biochemical oxygen demand (BOD)
2) Chemical oxygen demand (COD)
(B.O.D) is the amount of dissolved oxygen needed by aerobic biological organisms
in a body of water to break down organic material present in a given water sample
at certain temperature over a specific time period.
•
• (C.O.D.) is the amount of oxygen (in mg) required for the complete chemical
oxidation of organic and inorganic material in 1 litre of an effluent
4. Whey utilization and disposal
• Whey is a complete protein, lush with amino acids and so it can be
processed to produce a wide range of commercial products.
Some of the organisms used for utilization of whey for reducing the B.O.D.
Biotechnologically modified
organisms
Enzyme Function
Kluyveromyces sp. β-galactosidase Reduce lactose content
Bacillus licheniformis proteases Soluble whey proteins can be
hydrolyzed into amino acids and
peptides
Kluyveromyces fragilis,
Kluyveromyces marxianus
Lactose utilizing
enzymes
Reduce lactose content and
producing bioethanol
Lactobacillus Helveticus,
lactococcus lactis
subsp. Cremoris.
Kluyveromyces fraglis
Exo-polysaccharides
Converting lactose to
proteins
Improve the solubility
BOD reduction in whey
6. Application of recombinant DNA technology to waste treatment
procedures involve two steps
1) Finding a microorganism that has the desirable function (e.g., ability to
degrade a pesticide)
2) Transferring this desirable function to a suitable host, preferably a
microorganism with some relevance from an environmental viewpoint
Genetically manipulated strains of microbes for utilization of
whey or disposal of dairy waste in more economical way are
summarized below:
1) BOD Reduction :-
-Lactose utilizing yeasts such as Kluyveromyces sp. are important sources for the
production of β-galactosidase enzymes for reducing the lactose concentration
and BOD content.
7. 2) Single cell proteins :-
- single cell protein serves two functions-
(i) for reduction in pollution
(ii) creation of edible protein.
- The Kluyveromyces species have been most widely studied for SCP
production by converting lactose to protein into microbial biomass.
-The mixed culture of K. lactis and K. marxianus with S. cerevisiae was
reported to be viable and an attractive alternative for removal of BOD and
obtaining a valuable biomass yield.
3) Bio-ethanol :-
-Lactose-consuming S. cerevisiae strains, specifically involving the yeast
Kluyveromyces lactis, and also from Escherichia coli and Aspergillus niger
for the production of bio-ethanol from lactose.
8. 4) Exopolysaccharides (EPS)
-Modified lactic acid bacteria (LAB) such as Lactobacillus helveticus or
Lactococcus lactis subsp. cremoris are being successfully employed for the
production of EPS for use in various food formulations
5) Removal of toxic metals
-Zooglea ramigera, Bacillus licheniformis produce extracellular polymers
that are able to complex and subsequently accumulate metals such as
Fe,Cu,Ni,U. The accumulated metals can be easily released from the
biomass by treatment with acids.
6) Biological fuel cells
-Microorganisms can be used as electron donor in biological fuel cell (BFC)
for the conversion of organic matter into power
9. - One of the microbes exploited in this area is Rhodoferax ferrireducens.
- BFC generates electrical energy through the oxidation of biodegradable
organic matter in the presence of either fermentative bacteria or enzyme
under mild reaction conditions like ambient temperature and pressure
7) Biodegradation of oil
- Biodegration of oil spills is a major problem.
- A single bacterium cannot degrade all the components of oil which are
petroleum products.
- A strain of Pseudomonas putida that can degrade more than 3-4 compounds of
petroleum.
10. 8) Immobilized cell technology
- This high load of ammonia can be reduced by nitrifiers which convert
ammonia to nitrate and this ammonia is oxidised to nitrite by Nitrosomonas,
and then the nitrite is oxidised to nitrate by Nitrobacter.
