Light And Oxygen Impelling Rubrivivax Gelatinosus Directly Used Food Processing Wastewater To Accumulate Poly-β-Hydroxybutyrate, 5-Aminolevulinic Acid, Pigment

Background: Rubrivivax gelatinosus have the advantage of using wastewater to realize biomass recovery. However, they still cannot be large-scale applied because they cannot directly treat the wastewater containing macromolecular organics. Thus, this paper investigated the effect of light-oxygen condition on Rubrivivax gelatinosus (R. gelatinosus) directly recycling wastewater containing macromolecular organics to produce biomass, poly-β-hydroxybutyrate (PHB), 5-Aminolevulinic acid (5-ALA), pigment.Results: R. gelatinosus directly treated the macromolecules organic (soybean protein and starch) wastewaters and achieved biomass recovery under light-anaerobic and light-micro oxygen in six conditions. COD, protein, starch removals for two wastewaters all reached above 70%. Renewable bio-resource such as biomass, PHB, 5-ALA, pigment productions were 10 times of initial content. Theoretical analysis indicated that light activated two component signal pathway by stimulating its first hk gene expression, which regulated synthesis of protease and amylase. However, oxygen concentration decided the level of gene expression and the amount of enzymes. When oxygen was at micro-oxygen or anaerobic, above these expression and synthesis were conducted. Conclusion: In summary, this study expanded the view point ignored by traditional theory. It was realized that PNSB directly treated wastewater and accumulated nutrients (biomass, PHB, pigment and 5-ALA) for recycling, which reduced the secondary pollution of excess sludge to the environment.

Exploring the adaptive mechanism of Camellia limonia in karst high calcium environment via an integrative analysis of metabolomics and metagenomics

Background: Yellow Camellia is a kind of rare plant with high economic and medicinal value. It is known as the "giant panda" of the botanical world. Camellia group of plants (Camellia Sect. Chrysantha Chang) is the only golden flower of Theaceae. Compared with Camellia nitidissima, Camellia limonia grows in karst areas, where the soil has the characteristic of high calcium content. However, there are few studies about the Camellia limonia in karst soil environment and the adaptation mechanism is no clear. Results: In this study, we found that under high calcium treatment, the chlorophyll content and leaf areas of Camellia limonia increased, while those of Camellia nitidissima decreased. The photosynthetic efficiency of Camellia limonia was more stable and higher than Camellia nitidissima. Compared with Camellia nitidissima, the conductance was larger and the degree of leaf shrinkage was smaller in Camellia limonia. The metabolomics analysis showed that the kaempferol-3-o-rutinoside, tyrosol, 6-o-methyldeacetylisoipecoside and (r)-mandelic acid are the main differently metabolic compounds . The results of karst high calcium soil metagenomics showed that microbacterium-testaceum, intrasporangium-calvum and rubrivivax-gelatinosus significantly changed. Through metabonomics and metagenomics integrative analysis, flavone and flavonol biosynthesis is suggested to be the main regulation pathway, which is regulated by apigenin, kaempferol, astragalin, isoquercitrin metabolites and TT7, UGT78D1, UGT78D2 genes. This metabolic pathway involves the synthesis of flavonoids. Flavonoids have the functions in drought and salt resistance, which play an important role in the adaptation of Camellia limonia in karst high calcium environment.Conclusion: This omics study identified key regulation metabolites and genes for Camellia and provided important basis for the adaptive mechanism of plants to adapt to the high-calcium environment and the protection of Camellia species.

Protochlorophyllide synthesis by recombinant cyclases from eukaryotic oxygenic phototrophs and the dependence on Ycf54

The unique isocyclic E ring of chlorophylls contributes to their role as light-absorbing pigments in photosynthesis. The formation of the E ring is catalyzed by the Mg-protoporphyrin IX monomethyl ester cyclase, and the O2-dependent cyclase in prokaryotes consists of a diiron protein AcsF, augmented in cyanobacteria by an auxiliary subunit Ycf54. Here, we establish the composition of plant and algal cyclases, by demonstrating the in vivo heterologous activity of O2-dependent cyclases from the green alga Chlamydomonas reinhardtii and the model plant Arabidopsis thaliana in the anoxygenic photosynthetic bacterium Rubrivivax gelatinosus and in the non-photosynthetic bacterium Escherichia coli. In each case, an AcsF homolog is the core catalytic subunit, but there is an absolute requirement for an algal/plant counterpart of Ycf54, so the necessity for an auxiliary subunit is ubiquitous among oxygenic phototrophs. A C-terminal ∼40 aa extension, which is present specifically in green algal and plant Ycf54 proteins, may play an important role in the normal function of the protein as a cyclase subunit.