1. Recombinant enzymes for food
processing
Uzair Shah Hashmi

2. Food-processing enzymes from recombinant microorganisms
•food processing and in the production of food ingredients
Enzymes traditionally isolated from culturable microorganisms, plants, and mammalian
tissues are often not well-adapted to the conditions used in modern food production
methods
recombinant DNA technology steps in
manufacture novel enzymes suitable for specific food-processing conditions.
How ?
• by screening microorganisms sampled from diverse environments
•by modification of known enzymes using modern methods of
protein engineering
Advantages
Improvement of microbial production strains
• increase enzyme yield by deleting native genes encoding extracellular proteases
• fungal production strains have been modified to reduce or eliminate their potential for
production of toxic secondary metabolites

3. Improved pectinase production in Penicillium griseoroseum recombinant strains.
Experiments have done to obtain a recombinant organism that will be having the ability to
obtain pectin lyase (PL) and polygalacturonase (PG) and for that penicillium griseoroseum that
produced both PL &PG simultaneously.
•Firstly a strain that was reported to produce high concentration of PL was taken.
•It was then transformed using pAN52pgg2 plasmid which was having a foreign gene of PG of P.
grieoroseum and it was having a promoter from Aspergillus nidulans
•The newly transformed P. grieoroseum T20 when checked was producing higher concentrations
of both PG and PL, around 143 folds higher PL, and 15 folds greater PG.
•This recombinant strain uses carbon sources of low costs that is very economical
•The enzyme preparation commercially available is free of cellulolytic and proteolytic activities.
•This is an efficient system that uses P. griseoroseum to express and secrete proteins.

4. Chymosin

5. Also known as rennin
single polypeptide chain of 323 amino acids
•2 types differ only by one amino acid
Chymosin A (aspartic acid residue at position 286)
Chymosin B (glycine residue at position 286 )
‡
•Main coagulating enzyme
found in rennet which is used
extensively in cheese
production.
•hydrolyses a specific site in
kappa-casein of milk
•kappa-casein acts as micelle stabilizer
•‡Precipitation of insoluble constituents

7. Search for an alternative rennet
•increasing demand
•shortage of calf stomachs
•ethical issues with animal slaughtering
Kluyveromyces lactis
increase Chymosin production has been
made through expression of calf Chymosin
gene in recombinant K. lactis
Advantages of K. Lactis
•Non toxicogenic GRAS microorganism approved by US FDA
•‡Unlike p. Pastoris it does not require methanol to induce protein
secretion
•‡Unlike E. coli it doesn't secrete the expressed protein enclosed in
inclusion bodies

9. comparative study of 4 different recombinant chymosins
•Recombinant bovine Chymosin is the most frequently used
Chymosin in the industry
•new sources of recombinant Chymosin, such as goat, camel, or
buffalo, are now available.
When compared with other 3 enzymes
•Recombinant goat Chymosin exhibited the best catalytic efficiency
•recombinant goat Chymosin exhibited the best specific proteolytic
activity,
•recombinant goat Chymosin exhibited a wider pH range of action,
•recombinant goat Chymosin exhibited a lower glycosylation degree