Purple bacteria screening for photoautohydrogenotrophic food production: Are new H2-fed isolates faster and nutritionally better than photoheterotrophically obtained reference species?

Achieving Discharge Limits in Single-Stage Domestic Wastewater Treatment by Combining Urban Waste Sources and Phototrophic Mixed Cultures

“…However, when changing the COD:N ratio to 100:7 during Stage II, e.g., under organic substrate limiting conditions, this genus disappears almost entirely and is replaced by C39 in CSTR-1 and Rhodopseudomonas in CSTR-2. This result contradicts the generally accepted fact that the Rhodobacter genus is a k-strategist [30]. Nevertheless, the literature typically considers the growth strategy for the assimilation of organic substrates, not nutrients [42].…”

“…PPB were not able at any point to outcompete anaerobic chemoheterotrophic bacteria (Figure 7) and were strongly displaced by anaerobic chemoheterotrophs at the beginning of the operation in both reactors. Given their fermentative metabolism to generate VFA [30], these taxa strongly impacted the PPB development, so understanding their coexistence is critical to improving and developing robust wastewater treatment systems. This fact was not a detriment to PPB development, as the fermentative metabolism promotes PPB redox homeostasis by sugar fermentation and conversion into VFA that PPB The COD:N uptake ratio is another key factor that indicates the presence of assimilative bacteria as PPB in the culture, as shown previously in Figure 5 for the semicontinuous CSTR.…”

“…These anoxygenic photosynthetic microorganisms have gained interest due to their metabolic versatility, as they can grow chemotrophically in aerobic conditions and photoheterotrophically by obtaining energy from light in the IR spectrum [ 21 ]. Their secondary metabolism allows them to store C in the form of polyhydroxyalkanoates for the production of bioplastics [ 22 , 23 , 24 , 25 , 26 ], to accumulate P in the form of poly-P to be used as fertilizer [ 27 ], or to assimilate N to synthesize protein [ 28 , 29 ] of high biological quality due to their amino acids profile [ 30 ]. Also, mixed PPB cultures do not need strict anaerobic conditions to sustain the culture but rather a negative oxidation-reduction potential (ORP) [ 31 ].…”

Potential of enriched phototrophic purple bacteria for H2 bioconversion into single cell protein

“…Journal Pre-proof Hülsen et al, 2022cHülsen et al, , 2022b. However, the use of H 2 for PPB growth has received less attention (Madigan and Gest, 1979;Rey et al, 2006;Spanoghe et al, 2022Spanoghe et al, , 2021.…”

“…CO 2 from off-gases could be used as carbon source. The proof of concept of SCP production from H 2 using PPB pure cultures and autotrophic isolates has been recently conducted (Spanoghe et al, 2022(Spanoghe et al, , 2021. In this regard, the use of a mixed culture for the production of animal feed would lead to cost reduction due to non-sterile conditions.…”