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.
Keywords α-Amylase -
Bacillus cereus
- Biodegradable polymer - FTIR - GC - Lecithinase - PHA synthase - 16S rRNA gene