Polyhydroxyalkanoates (PHAs) as one of biomaterials to replace plastics are intracellular energy storage linear polyesters produced in nature by bacterial fermentation of sugar and lipids. Due to biocompatibility and biodegradability of biologically-produced PHA for possible uses as plastics with promising physical and chemical characteristics (e.g., can be changed by blending and/or modifying the surface), PHAs could be applicable to be biodegradable polymers for green technology of sustainable development [1]. Several naturally-occurring microbes were reported to have capabilities of PHA biosynthesis (e.g., Azotobacter vinelandii [3], Pseudomonas sp. [4] and Aeromonas sp. [5]). Regarding the bacteria that generated PHAs in different monomer compositions via diverse synthetic pathways for fermentative production, Aeromonas hydrophila were often popularly studied.
Due to this, this study tended to explore optimal operation strategy of PHA production using indigenous dye-decolorizing bacterium A. hydrophila NIU01 [10] for wastewater treatment and materials recycling and reuses afterwards. Recently, prior study [11] also showed the promising capability of PHA synthesis for A. hydrophila in the presence of decolorized intermediate(s) for wastewater decolorization. However, optimal strategy of operation to cellular capability of PHA synthesis was remained open to be explored for promising feasibility to practical applications. Thus, indigenous dye-decolorizing bacterium A. hydrophila NIU01 was selected to explore whether using coconut oil-bearing MR medium could significantly stimulate synthetic capabilities of PHAs.
As this study tends to explore operation strategy for
materials recycling during dye-containing wastewater treatment,
dye-decolorizer Aeromonas hydroiphila NIU01 which also owned
significant tolerant capabilities to dyes and decolorized intermediates
was used for study, but not popularly-used PHB-producing
bacteria (e.g., Ralstonia eutropha)[11].This feasibility study showed
that separation cell growth phase from PHA production phase of A.
hydrophila NIU01 using two-stage fermentation strategy to maximize
PHA production was technically viable.