It was reported that PhaP3 was a major phasin in the phaP1-deficient PS341 mutant of R. eutropha[40]; therefore, the release of PhaR from the phaP3 region may occur only in the absence of PhaP1. A previous observation suggested that PhaP2 (PHG202) was not present on the granule surface in vivo, whereas the expression level of phaP2 was very high in the growth and PHA production phases. Another study suggested that PhaP2 may have indirectly participated

in the formation of P(3HB) granule by interacting with other phasins [41]. In our study, phaP4 (H16_B2021) was expressed during cultivation with the lower level than phaP1 and phaP2. PhaP5 (H16_B1934) [41], PhaP6 (H16_B1988) and PhaP7 (H16_B2326) [42], and PhaM (H16_A0141) [43] were recently identified as FG-4592 supplier new granule-associated proteins, although the expression levels of their corresponding genes were observed to be very low. The weak expression level of phaP5 in F26 markedly contradicted with a previous microarray analysis [22]; hence, further validation will be necessary.

R. eutropha possesses 5 PHA depolymerases with a DepA domain (phaZ1-Z5), 2 additional depolymerases with an LpqC domain (phaZ6 and phaZ7) and 2 hydroxybutyrate oligomer hydrolases (phaY1 and phaY2) that are considered to be involved in mobilization of P(3HB). Despite the cellular phases examined in the present study were not the PHA utilization phase, the expression levels of phaZ4 (PHG178) and phaY2 (H16_A1335) in the growth phase; and phaZ1 (H16_A1150) and phaZ6 (H16_B2073) in the

PHA production phase were rather higher than those of others. Transporters Kaddor et al. demonstrated that Aldol condensation the fructose-specific ABC-type transporter FrcACB, which is encoded within the sugar degradation gene cluster 1, was essential for the growth of R. eutropha H16 on fructose [44]. We observed significant down-regulation of these genes in the PHA production phase compared with the growth phase, as described above (Figure 2 and Additional 1: Table S3). The weak expression level of frcACB may be sufficient to support an PF-04929113 price adequate carbon flux for PHA biosynthesis, or other transporters may have roles in this process. However, the resent microarray analysis reported up-regulation of the fructose transporter genes during nitrogen starvation [22]. copP2 (H16_A3668), which encodes a putative copper uptake P-type ATPase; and nosFD (PHG249-PHG250), which encodes putative copper-specific ABC transporter subunits, were highly up-regulated in the growth phase along with copDCBA (H16_B2182-B2185) and copZ (H16_A3669) (Additional file 1: Table S3), which confer resistance to copper. The up-regulation of these genes was estimated to be due to formation of active copper-containing enzymes, such as cytochrome c oxidase, in an aerobic respiratory chain [45]. 13CO2 Fixation into P(3HB) synthesized from fructose in the presence of NaH13CO3 by R.