1. Introduction
Synthetic plastic plays an important role in human daily life but causes widespread environmental
pollution as a consequence of recalcitrant properties [1]. Bioplastic, a biodegradable plastic, has been
developed to replace synthetic plastic. One of the most well-known bioplastics is PHA. PHA is mostly
synthesized by PHA-producing bacteria as an energy source material when the bacteria are grown under
unbalanced conditions, such as a shortage of nitrogen phosphate and oxygen but the content of the carbon
source is excessive [2]. PHA is the only 100% biodegradable polymer [3]. However, it is less admissible than
the other bioplastics due to its high cost which is raised by the carbon source for bacteria [4]. Therefore,
various attempts have been devoted to the development of economical processes or the search for suitable
wastes as carbon sources in order to lower the production cost. Presently, PHA production from activated
sludge produced from wastewater treatment system has been noted. PHA accumulation in activated sludge in
a SBR system fed with several types of wastewater has been studied [5]-[7]. However, little information is
available on the use of CSW and especially the use of PHA-producing bacteria as seed. Cassava starch is one
of the major industries of Thailand. Thus, this study aims to investigate the potential of CSW for PHA
production from a SBR system which was seeded with Bacillus tequilensis MSU 112, a PHA-producing
bacterial strain. The treatment efficiency of the SBR system was also determined.