Isolation and Selection of PHA Producing Bacteria. A
wide variety of bacteria are known to accumulate PHA.
Today, approximately 150 different hydroxyalkanoic acids are
known to be incorporated into polyhydroxyalkanoates [20],
with microbial species from over 90 genera being reported
to accumulate these polyesters [21]. These bacteria have
been reported from various environments, but only a few
from the waste water and sludge ecosystems. For the rapid
detection and isolation of PHB producing bacteria, 0.02%
alcoholic solution of Sudan black B and Nile blue A staining
viable colony method [14] was used. The isolation of PHA
producing bacteria was done from cardboard manufacturing
industry waste water and pulp cardboard and kraft industry
sludge. A large proportion about 35% of isolated bacteria
produced PHA as energy reserve material. A total of 42
isolates showed black-blue coloration when stained with
Sudan black B, a preliminary screening agent for lipophilic
compounds, and a total of 15 isolates showed positive result
with Nile blue A staining (Figure 1), a specific dye for the
of PHA granules. Both gram-positive and gram-negative
bacteria showed PHA production, but gram-positive bacteria
dominated the waste material microflora of pulp, kraft, and
cardboard manufacturing industry. Teeka et al. [22] used this
method to screen the potential PHA producing bacteria from
soil, and Ramachandran and Abdullah [23] also observed