Among the various initial [PO4 3-] theted, the medium containing initially 25 mM of [PO4 3-] resulted in the higher polymer production after 72 h of cultivation (Table 1), consistent with the report that the initial [PO4 3-] in the culture medium influences both the cell density and the PHAs production (Lee et al. 2000).
Thus, following the preliminary experiments in which we investigated the influence of carbon source on PHAs and PLs production in culture media containing initially 36 mM of phosphates we examine the influence of various initial phosphate concentrations (ranging from 0.5-50 0.5-504 3-] on both products synthesis.
The chemical by-products were also identified and quantified in the final oxidized solution: acetic acid and ammonia were identified in all samples as the major by-products representing around 31%and69%9%, respectively, of residual TOC and initial nitrogen after the oxidation of a representative sample of ABPs containing initially 5 g L−1 of total organic carbon (TOC).
However, RLs production and its yield were 2 and 3 times respectively lower than that obtained in culture medium containing initially 0.5 mM of [PO4 3-] (Table 1).
In contrast, phosphate was not limited in culture media containing initially 50 mM of [PO4 3-], even after 72 h of cultivation, resulting in the highest cell concentration, 1120 mg/L as illustrated in Figure 2e.
Phosphorus was early limited, approximately after 15 h of cultivation, in the culture medium containing initially 5 mM of [PO4 3-] resulting in a biomass production of 840 mg/L (Figure 2b).
PHAs accumulation was enhanced (> 300 mg/L) after 72 h of cultivation in an initial [PO4 3-] of 25 mM, while RLs production (> 200 mg/L) was started after 35 h and continued until 72 h of cultivation, in a phosphate-limited medium containing initially 5 mM of [PO4 3-].
As a conclusion, CER/DBP (70/30), for example, is referred to the CER film containing initially 30 wt% of DBP; CERDBP30 is related to the corresponding film obtained after Soxhlet extraction, and a-CERDBP30 is used to name the sample obtained after Soxhlet extraction and additional thermal treatment at 250 °C for 2 h.
Each peptide or protein was tested separately, with each treatment and control initially containing 16 individuals.
A number of clues submitted contained an initially mysterious reference to Dr Who, until I realized that the clue phrase contains most of the letters of Matt Smith, the actor currently playing the doctor.
