Production of polyhydroxyalkanoate from starch by the native isolate Bacillus cereus CFR06

A bacterial strain that produces amylase and
polyhydroxyalkanoate (PHA) was isolated, identified, and
classified under the Bacillus cereus group based on 16S
rRNA gene sequences and specific reaction in poly-myxin
egg yolk Mannitol bromothymol blue agar (PEMBA)
medium and in combination with microbiological and
biochemical tests. The complete ORF of phaC gene was
cloned by PCR technique and nucleotide sequences were
determined. Results indicated that the phaC gene had 99%
homology with phaC of B. cereus (AE016877.1), 98% with
B. thuringiensis (AY331151.1), and 94% with several
strains of B. anthracis and B. cereus group including
Bacillus sp. INT005. However, only 90% sequence
homology with phaC of B. megaterium (AF109909.2) was
observed. The PHA production using different fermentable
sugars was tested and it was found that the CFR06 was able
to accumulate 36–60% of PHA in cell dry weight (CDW).
Zymogram of amylase indicated that native strain produces
an extracellular enzyme of *80 kDa. The potency of the
organism to hydrolyze starch due to the intrinsic amylase
activity was considered, and starch was used as the sole
carbon source for growth and PHA production. GC, FTIR,
and 1H NMR analysis of the polymer indicated that the
strain was a potent polyhydroxybutyrate (PHB) producer.
The bacterium accumulated about 48% PHA in CDW in a
starch containing medium.