Table 2 Unique features of reduced genomes of Escherichia coli and Bacillus subtilis

Escherichia coli K-12

Large scale deletions

Aberrant cell morphology

Increased doubling time

Changed nucleoid organization

[76]

E. coli K-12

Mobile DNA,

Cryptic virulence genes

Normal cell growth and protein expression, comparable to parental strain

MDS42 cells exhibit high electroporation efficiency and propagation of unstable plasmid

[77]

E. coli K-12

Biosynthesis genes for some amino acids, lipopolysaccharides and phosphor lipids

Transporter genes, ISs and toxin-antitoxin pairs

Growth was as rapid as the parental strain in minimal medium (M9) during exponential phase.

Mutant strain continued whereas wild type strain progressed to the stationary phase

MGF-01 secreted higher (2.44-fold) threonine compared to wild type strain

[75]

Bacillus subtilis

Prophages – SPβ, PBSX

Prophage like sequences – pro1, pro3, skin (sigK intervening)

pks operon

No unique properties including AmyQ protein secretion

Increase in heterologous amylase secretion

[32]

B. subtilis

All prophages

All prophage like sequences except pro7

pks and pps operons

Cell growth was normal

No beneficial properties were apparent

[79]

B. subtilis

All prophage

All prophage like sequences except pro7

pks, pps operon and 6 deletions

Unstable phenotypes with regard to growth rate, cell morphology and recombinant protein production

[79]

B. subtilis

Eleven non essential gene cluster i.e. 865genes

Genes essential for spore formation including spoIIIC and spoIVCB

Enhanced productivity of extracellular cellulase and protease

Reduced growth rate (30% in LB, 50% in SMM

compared with wild type B. subtilis 168 strain

Did not form spores

Improved efficiency of carbon source utilisation

[61]