dry cell weight, PHB content, and concentrations were 9.00 and 11.03 g L−1,
51.33 and 54.45%, and 4.62 and 5.67 g L−1, respectively. The corresponding
average PHB concentrations were 3.90 and 3.80 g L−1,
respectively. Thus, the optimal C/N ratio of 60/1 for PHB synthesis
(Fig. 5) was also confirmed with batch data using nitrogen-limited
medium as aforementioned in Fig. 4. This study suggested that twostage
fermentation was a technically-feasible mode of operation
to stimulate significant accumulation of target product(s) when
cell growth was reached in stationary phase. Follow-up studies
will explore the feasibility of using trace metals for supplementation
and fed-batch culture with exponentially-feeding strategy
to reach optimal of high cell-density cultivation for maximal
PHB production [20]. In addition, as strain NIU01 is a promising
dye-decolorizing and bioelectricity-generating bacterium, the
strategy of PHB production and power generation for materials and
energy recycling during dye-bearing wastewater treatment will be
conducted afterwards for considerations of cradle-to-cradle environmental
bioremediation.