Beschreibung:
Three sequential batch reactors were operated for microbial enrichment at the same time under exactly the same operational conditions (organic loading rate, hydraulic and solids retention time, cycle length, C/N ratio) just with the solely difference of the working temperature: psychrophilic (15°C); mesophilic (30°C); and thermophilic (48°C). The microbial communities enriched showed different behaviours in terms of consumption and production rates. In terms of PHA accumulation, the psychrophilic community was able to accumulate an average amount of 17.7 ± 5.7 wt% PHBV; the mesophilic 40.3 ± 7.0 wt% PHBV, and the thermophilic 14.8 ± 0.3 wt% PHBV in dry weight over total solids. The average PHBV production yields for each selected community were 0.41 ± 0.12 Cmmol PHBV /CmmolVFA at 15°C, 0.64 ± 0.05 Cmmol PHBV /Cmmol VFA at 30°C, and 0.39 ± 0.14 Cmmol PHBV /Cmmol VFA at 48°C. It can be seen that the overall performance of the mesophilic reactor was better than the other two, and the PHBV copolymers obtained at this temperature contained a higher PHV fraction. The physico-chemical properties of the obtained biopolymers at each temperature were also measured in the present study so as to compare them. Minor variations were observed in terms of thermal properties and main differences were found in the molecular weight, which followed an increasing trend with the temperature