Purification of AS-CMP effluent by combined photosynthetic bacteria and coagulation treatment

The effluent from the pulping of E. urophylla by alkali sodium sulfite chemi mechanical process(AS-CMP) was characterized for its biodegradability by photosynthetic bacteria (PSB). Chemical coagulation post treatment of biotreated wastewater was also studied. One month continuous treatment in the laboratory indicated that the COD Cr , BOD 5 and SS removals in biotreatment stages reached 56%, 83% and 89% respectively, and the CH 2Cl 2 extractives decreased from 10.7 mg/L to 7.7 mg/L. In chemical coagulation post treatment stage, the effects of process conditions, such as coagulant dosage, pH value and the coordinated coagulation flocculation treatment of three kinds of coagulants on coagulation effectiveness were discussed. The optimum operating conditions were given.

In vitro assessment of gastrointestinal viability of two photosynthetic bacteria,Rhodopseudomonas palustris and Rhodobacter sphaeroides

The objectives of this study were to assess the potential of two photosynthetic bacteria （PSB）, Rhodopseudomonas palustris HZ0301 and Rhodobacter sphaeroides HZ0302, as probiotics in aquaculture. The viability of HZ0301 and HZ0302 in simulated gastric transit conditions （pH 2.0, pH 3.0 and pH 4.0 gastric juices） and in simulated small intestinal transit conditions （pH 8.0, with or without 0.3% bile salts） was tested. The effects of HZ0301 and HZ0302 on the viability and permeability of intestinal epithelial cell in primary culture of tilapias, Oreochrornis nilotica, were also detected. All the treatments were deter- mined with three replicates. The simulated gastric transit tolerance of HZ0301 and HZ0302 strains was pH-dependent and correspondingly showed lower viability at pH 2.0 after 180 min compared with pH 3.0 and pH 4.0. Both HZ0301 and HZ0302 were tolerant to simulated small intestine transit with or without bile salts in our research. Moreover, there was no significant difference （P〉0.05） among three treatments including the control and the groups treated with HZ0301 or HZ0302 both in intestinal epithelial cell viability and membrane permeability, showing no cell damage. In summary, this study demonstrated that HZ0301 and HZ0302 had high capacity of upper gastrointestinal transit tolerance and were relatively safe for intestinal epithelial cells of tilapias.

Biological treatment of high NH_4^+-N wastewater using an ammonia-tolerant photosynthetic bacteria strain (ISASWR2014)

Wastewater with high NH_4^+-N is difficult to treat by traditional methods.So in this paper,a wild strain of photosynthetic bacteria was used for high NH_4^+-N wastewater treatment together with biomass recovery.Isolation,identification,and characterization of the microorganism were carried out.The strain was inoculated to the biological wastewater treatment unit.The impacts of important factors were examined,including temperature,dissolved oxygen,and light intensity.Results showed that photosynthetic bacteria could effectively treat high NH_4^+-N wastewater.For wastewater with NH_4^+-N of 2300 mg·L^(-1),COD/N=1.0,98.3%of COD was removed,and cell concentration increased by 43 times.The optimal conditions for the strain's cell growth and wastewater treatment were 30℃,dissolved oxygen of 0.5-1.5 mg·L^(-1) and a light intensity of 4000 lx.Photosynthetic bacteria could bear a lower C/N ratio than bacteria in a traditional wastewater treatment process,but the NH_4^+-N removal was only 20%-40%because small molecule carbon source was used prior to NH_4^+-N.Also,the use of photosynthetic bacteria in chicken manure wastewater containing NH4+-N about 7000 mg·L^(-1) proved that photosynthetic bacteria could remove NH_4^+-N in a real case,finally,83.2%of NH_4^+-N was removed and 66.3%of COD was removed.

Generation of Hydrogen from Photolysis of Organic Acids by Photosynthetic Bacteria

Photodecomposition of ten kinds of organic acids by Rhodopseudomonas palustris for producing hydrogen has been investigated. By using acetate as hydrogen donor, dynamics of hydrogen production and cell growth has been determined; the influences of acetate concentration, temperature, light intensity and the effects of the interaction among metal ions (Fe3+, Ni2+), acetate and glutamate in aqueous solution on hydrogen production have been examined for optimizing the conditions of H2 generation. The results show that H2 production is partially correlated with cell growth; Ni2+ inhibits hydrogen production, but enhances cell growth; Fe3+ promotes hydrogen production evidently. The highest rate of H2 production is 22.1 mL L-1 h-1 under the conditions of 35 ~ 37℃, 6000 ~ 8000 lx, 30 mmolL-1 of acetate, 9 mmolL-1 of glutamate, and 50 mmolL-1 of Fe3+.

Biological formation of 5-aminolevulinic acid by photosynthetic bacteria

In this study, 7 stains of Rhodopseudomonas sp. were selected from 36 photosynthetic bacteria stains storied in our laboratory. Rhodopseudomonas sp. strain 99 28 has the highest 5 aminolevulinic acid(ALA) production ability in these 7 strains. Rhodopseudomonas sp. 99 28 strain was mutated using ultraviolet radiation and a mutant strain L 1, which ALA production is higher than wild strain 99 28 about one times, was obtained. The elements affecting ALA formation of strain 99 28 and L 1 were studied. Under the optimal condition(pH 7 5, supplement of ALA dehydratase(ALAD) inhibitor, levulinic acid(LA) and precursors of ALA synthesis, glycine and succinat, 3000 lx of light density), ALA formation of mutant L 1 was up to 22 15 mg/L. Strain L 1 was used to treat wastewater to remove COD Cr and produce ALA. ALA production was 2 819 mg/L, 1 531 mg/L, 2 166 mg/L, and 2 424 mg/L in monosodium glutamate wastewater(MGW), succotash wastewater(SW), brewage wastewater(BW), and citric acid wastewater(CAW) respectively. More than 90% of COD Cr was removed in four kinds of wastewater. When LA, glycin and succinate were supplied, ALA production was dramatically increased, however, COD Cr could hardly be removed.

Effects of Different Concentrations of Photosynthetic Bacteria Solutions on Yield and Quality of Lactuca sativa L.

The effects of different concentrations of photosynthetic bacteria solutions （CK, 0 ml photosynthetic bacteria agent＋4 000 ml nutrient solution; T1, 200 ml pho- tosynthetic bacteria agent＋3 800 ml nutrient solution; T2, 400 ml photosynthetic bacteria agent＋3 600 ml nutrient solution; T3, 600 ml photosynthetic bacteria agent＋ 3 400 ml nutrient solution; T4, 800 ml photosynthetic bacteria agent＋3 200 ml nutrient solution; and T5, 1 000 ml photosynthetic bacteria agent＋3 000 ml nutrient solu- tion） on the leaf number, fresh mass, root vigor, vitamin C content, soluble sugar content, soluble protein content and nitrate content of hydroponic Lactuca sativa L. were investigated. The results showed that the leaf number was increased by 62.66%, the fresh mass was increased by 139.7%, the root vigor was increased by 132.04%, the vitamin C content was increased by 18.34%, the soluble protein content was increased by 16.60%, the soluble sugar content was increased by 192.37%, and the nitrate content was reduced by 69.44% in the T3 group com- pared with those in the control group. The photosynthetic bacteria solution in the T3 group reduced the content of nitrate and improved the yield and quality of hydroponic L. sativa.

Effects of Photosynthetic Bacteria-enhanced Biological Floc Replacement Diets on Tilapia Growth,Water Environment and Water Microbial Diversity

With Oreochromis niloticus as the object of study,glucose was added as a carbon source to promote the formation of the biological flocs for replacing part of the feed,and three gradients were set up,namely Group A(all feed),Group B(replacement of 10%feed)and Group C(replacement of 20%feed),so as to explore the effects of photosynthetic bacteria-enhanced biological flocs on tilapia growth and water environment conditions.Meanwhile,the Biolog-ECO technology was applied to study the changes of microbial carbon metabolism diversity in aquaculture water.The results showed that the utilization of microbial carbon sources under different feed replacement gradients increased with the extension of the culture time.The overall performance was in order of 10%replacement>all feed>20%feed replacement.A suitable replacement rate could not only enhance the overall utilization of carbon sources by water microorganisms,but also save culture costs.The principal component analysis showed that the carbon source metabolism of the water microbial communities under different feed replacement gradients was significantly different.Specifically,polysaccharides,esters and amino acids were the preferred carbon sources of water microbes,while the utilization of amines and acids was low.

Treatment of Chinese Traditional Medicine Wastewater by Photosynthetic Bacteria

The influence factors treating wastewater of Chinese traditional medicine extraction by photosynthetic bacteria are tested and discussed. The results indicate that the method of photosynthetic bacteria can eliminate COD and BOD from wastewater in high efficiency. And it also has high load shock resistance. On the conditions of slight aerobic and semi-darkness, treating wastewater of Chinese traditional medicine extraction, the method has better efficiency to eliminate COD and BOD from the wastewater than those by anaerobic illumination and aerobic darkness treatments. After pretreatment of hydrolytic acidization, the removal rate of COD in the wastewater reached more than 85 %, and that rate of BOD reached more than 90% in the treating system of photosynthetic bacteria. It may be more feasible and advantageous than traditional anaerobic biological process to treat organic wastewater using PSB system.

Tailoring therapeutics via a systematic beneficial elements comparison between photosynthetic bacteria-derived OMVs and extruded nanovesicles

Photosynthetic bacteria(PSB)has shown significant potential as a drug or drug delivery system owing to their photothermal capabilities and antioxidant properties.Nevertheless,the actualization of their potential is impeded by inherent constraints,including their considerable size,heightened immunogenicity and compromised biosafety.Conquering these obstacles and pursuing more effective solutions remains a top priority.Similar to extracellular vesicles,bacterial outer membrane vesicles(OMVs)have demonstrated a great potential in biomedical applications.OMVs from PSB encapsulate a rich array of bioactive constituents,including proteins,nucleic acids,and lipids inherited from their parent cells.Consequently,they emerge as a promising and practical alternative.Unfortunately,OMVs have suffered from low yield and inconsistent particle sizes.In response,bacteria-derived nanovesicles(BNVs),created through controlled extrusion,adeptly overcome the challenges associated with OMVs.However,the differences,both in composition and subsequent biological effects,between OMVs and BNVs remain enigmatic.In a groundbreaking endeavor,our study meticulously cultivates PSB-derived OMVs and BNVs,dissecting their nuances.Despite minimal differences in morphology and size between PSB-derived OMVs and BNVs,the latter contains a higher concentration of active ingredients and metabolites.Particularly noteworthy is the elevated levels of lysophosphatidylcholine(LPC)found in BNVs,known for its ability to enhance cell proliferation and initiate downstream signaling pathways that promote angiogenesis and epithelialization.Importantly,our results indicate that BNVs can accelerate wound closure more effectively by orchestrating a harmonious balance of cell proliferation and migration within NIH-3T3 cells,while also activating the EGFR/AKT/PI3K pathway.In contrast,OMVs have a pronounced aptitude in anti-cancer efforts,driving macrophages toward the M1 phenotype and promoting the release of inflammatory cytokines.Thus,our findings not only provide a promising methodological framework but also establish a definitive criterion for discerning the optimal application of OMVs and BNVs in addressing a wide range of medical conditions.

Polydopamine-coated photoautotrophic bacteria for improving extracellular electron transfer in living photovoltaics

Living photovoltaics are microbial electrochemical devices that use whole cell–electrode interactions to convert solar energy to electricity.The bottleneck in these technologies is the limited electron transfer between the microbe and the electrode surface.This study focuses on enhancing this transfer by engineering a polydopamine(PDA)coating on the outer membrane of the photosynthetic microbe Synechocystis sp.PCC6803.This coating provides a conductive nanoparticle shell to increase electrode adhesion and improve microbial charge extraction.A combination of scanning electron microscopy(SEM),transmission electron microscopy(TEM),UV–Vis absorption,and Raman spectroscopy measurements were used to characterize the nanoparticle shell under various synthesis conditions.The cell viability and activity were further assessed through oxygen evolution,growth curve,and confocal fluorescence microscopy measurements.The results show sustained cell growth and detectable PDA surface coverage under slightly alkaline conditions(pH 7.5)and at low initial dopamine(DA)concentrations(1 mM).The exoelectrogenicity of the cells prepared under these conditions was also characterized through cyclic voltammetry(CV)and chronoamperometry(CA).The measurements show a three-fold enhancement in the photocurrent at an applied bias of 0.3 V(vs.Ag/AgCl[3 M KCl])compared to non-coated cells.This study thus lays the framework for engineering the next generation of living photovoltaics with improved performances using biosynthetic electrodes.

Effects of Combinations of Two of Three Different Probiotics on Pond Water Quality

In order to provide reference for probiotics application in aquaculture, Bacillus subtilis （A）, Streptococcus faecalis （B） and photosynthetic bacteria （C） were prepared according to the ratios of 9：1, 4：1, 1：1, 1：4 and 1：9 with 10^5 cfu/ml as the unit of concentration into 15 mixed microecological preparations, and their effects on COD, ammonia nitrogen, nitrite nitrogen and sulfide in pond water were investigated. The results showed that the mixed preparation of B. subtilis and photosynthetic bacteria at a ratio of 1：4 had the best effect in treating COD （P〈0.05）, the mixed preparation of B. subtilis and S. faecalis at a ratio of 4：1 showed the best effect in treating ammonia nitrogen （P〈0.05）, the mixed preparation of S. faecalis and photosynthetic bacteria at a ratio of 4：1 showed the best effect in treating nitrite nitrogen （P〈0.05）, and the mixed preparation of Streptococcus faecalis and photosynthetic bacteria at a ratio of 9：1 had the best effect of reducing sulfide （P〈0.05）.

Subcloning and Sequencing of the Form II Ribulose 1,5-Bisphosphate Carboxylase/Oxygenase from Rhodopseudomonas palustris

Rhodopseudomonas palustris, one of purple nonsulfur photosynthetic bacteria, fixes carbon dioxide via Calvin-Benson cycle and has been shown previously to express form I and form II ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO). The gene cbbM, which encodes the form II enzyme from Rhodopseudomonas palustris, has been subcloned and sequenced. The deduced amino acid sequence is highly with the form II RubisCO from photosynthetic bacteria, including Rhodospirillum rubrum (PDB ID: 9rub), but appears to be more distantly related to the large subunit of the form I RubisCO found in photosynthetic bacteria, chemoautotrophic bacteria and higher plants. Several regions highly conserved among L 8S 8 and L x enzymes correspond with regions previously implicated in catalytic activity and subunit interactions.

Effect of Photo-Oxidation on Energy Transfer in Light Harvesting Complex （LH2） from Rhodobacter Sphaeroides 601

We study the photo-oxidation of bacteriochlorophylls （BChls） in peripheral light harvesting complexes （LH2） from rhodobacter sphaeroides by using the steady absorption and the femtosecond pump-probe measurement, to realize the detailed dynamics of LH2 in the presence of photo-oxidation. The experimental results reveal that BChl-B850 radical cations may act as an additional channel to compete with the unoxidized BChl-B850 molecules for rapidly releasing the excitation energy, while the B800→B850 energy transfer rate is almost unaffected in the oxidation process.

In vivo polydopamine coating of Rhodobacter sphaeroides for enhanced electron transfer

Recent advances in coupling light-harvesting microorganisms with electronic components have led to a new generation of biohybrid devices based on microbial photocatalysts.These devices are limited by the poorly conductive interface between phototrophs and synthetic materials that inhibit charge transfer.This study focuses on overcoming this bottleneck through the metabolically-driven encapsulation of photosynthetic cells with a bio-inspired conductive polymer.Cells of the purple non sulfur bacterium Rhodobacter sphaeroides were coated with a polydopamine(PDA)nanoparticle layer via the self-polymerization of dopamine under anaerobic conditions.The treated cells show preserved light absorption of the photosynthetic pigments in the presence of dopamine concentrations ranging between 0.05–3.5 mM.The thickness and nanoparticle formation of the membrane-associated PDA matrix were further shown to vary with the dopamine concentrations in this range.Compared to uncoated cells,the encapsulated cells show up to a 20-fold enhancement in transient photocurrent measurements under mediatorless conditions.The biologically synthesized PDA can thus act as a matrix for electronically coupling the light-harvesting metabolisms of cells with conductive surfaces.

Cryomicroneedle delivery of nanogold-engineered Rhodospirillum rubrum for photochemical transformation and tumor optical biotherapy

Tumor metabolite regulation is intricately linked to cancer progression.Because lactate is a characteristic metabolite of the tumor microenvironment(TME),it supports tumor progression and drives immunosuppression.In this study,we presented a strategy for antitumor therapy by developing a nanogold-engineered Rhodospirillum rubrum(R.r-Au)that consumed lactate and produced hydrogen for optical biotherapy.We leveraged a cryogenic micromolding approach to construct a transdermal therapeutic cryomicroneedles(CryoMNs)patch integrated with R.r-Au to efficiently deliver living bacterial drugs.Our long-term storage studies revealed that the viability of R.r-Au in CryoMNs remained above 90%.We found that the CryoMNs patch was mechanically strong and could be inserted into mouse skin.In addition,it rapidly dissolved after administering bacterial drugs and did not produce by-products.Under laser irradiation,R.r-Au effectively enhanced electron transfer through Au NPs actuation into the photosynthetic system of R.rubrum and enlarged lactate consumption and hydrogen production,thus leading to an improved tumor immune activation.Our study demonstrated the potential of CryoMNs-R.r-Au patch as a minimally invasive in situ delivery approach for living bacterial drugs.This research opens up new avenues for nanoengineering bacteria to transform tumor metabolites into effective substances for tumor optical biotherapy.