Characteristics of the rhizosphere and phyllosphere microbial community of three submerged plants in the dragon-shaped water system of Beijing / 生物工程学报

Aquatic plants and the epiphytic microorganisms are important contributors to the purification of constructed wetlands. Taking the dragon-shaped water system of Beijing Olympic Park as a model, this study analyzed the structure and function of the microbial communities reside the sediment, the water body and the rhizosphere and phyllosphere of three submerged plants-Vallisneria natans, Myriophyllum verticillatum, and Potamogeton pectinatus using high-throughput sequencing technology. The results showed that the microbial diversity from the highest to the lowest were samples from sediment, plant rhizosphere, plant phyllosphere and water. The microbial diversity of plant phyllosphere samples were significantly higher than those of the water body. LEfSe analysis showed that different habitats enriched different microbial groups. The sediments mainly enriched anaerobic microbes, while the water body and the phyllosphere of plants mainly enriched aerobic microbes, and the rhizosphere of plants had the both. Functional prediction analysis showed that the abundance of denitrification marker genes in phyllosphere samples was higher than that in samples from rhizosphere, sediment and water body, and the abundance of denitrification marker genes in phyllosphere samples of M. verticillatum and P. pectinatus was higher than that of V. natans. This study could serve as a guidance for the selection of submerged plants and functional microorganisms for constructed wetlands.

ELECTRA: electricity-driven low energy and chemical input technology for accelerated bioremediation / 生物工程学报

The international cooperation project "electricity-driven low energy and chemical input technology for accelerated bioremediation" (abridged as "ELECTRA") is jointly supported by National Nature Science Foundation of China (NSFC) and European Commission (EC). The ELECTRA consortium consists of 5 research institutions and universities from China and 17 European research institutions and universities, as well as high-tech companies of EC countries. ELECTRA focuses on researches of biodegradation of emerging organic compounds (EOCs) and novel environmental biotechnologies of low-energy and low-chemical inputs. The project has been successfully operated for 2 years, and has made important progresses in obtaining EOCs-degrading microbes, developing weak-electricity-accelerated bioremediation, and 3D-printing techniques for microbial consortium. The ELECTRA has promoted collaborations among the Chinese and European scientists. In the future, ELECTRA will overcome the negative impact of the COVID-19 pandemic and fulfill the scientific objectives through strengthening the international collaboration.

Environmental scientists & microbiologists from China & EU: take the responsibility to cherish the Earth homeland / 生物工程学报

Humanity shares the common interest to protect the environment and to maintain a healthy global ecosystem. International collaboration is key in this context, to advance the necessary science and technology. The National Science Foundation of China (NSFC) and European Commission (EC) have agreed to collaborate in innovative knowledge and technology in the field of bioremediation of polluted environments and biodegradation of plastics. In this context, projects on bioremediation of soils, wastewater and sediment matrices and on microbial degradation of plastics were supported. This special issue aimed to introduce these projects and their progresses in the related fields. In total, 23 papers have been collected in this issue, covering both fundamental and applied researches.

Biosynthesis of poly (3-mercaptopropionate) and poly (3-mercaptopropionate-co-3-hydroxybutyrate) with recombinant Escherichia coli / 生物工程学报

Polythioesters newly emerged as a type of novel polymer and they have showed great potential for application in industries. In this study, genes of butyrate kinase (buk) and phosphotransbutyrylase (ptb) from Clostridium acetobutylicum, and poly (3-hydroxybutyrate) (PHB) synthase gene from Thiocapsa pfennigii were used for construction of a metabolic pathway to synthesize the polythioesters. When 3-mercaptopropionate and 3-hydroxybutyrate were fed, poly (3-mercaptopropoinate) [poly (3MP)] and poly(3-mercaptopropionate-co-3-hydroxybutyrate) [poly(3MP-co-3HB)] were synthesized by recombinant Escherichia coli JM109 (pBPP1) harboring the constructed metabolic pathway. Results indicated clearly that all these genes are necessary for the synthesis of poly(3MP) and poly(3MP-co-3HB).

Biosynthesis and accumulation of poly(3-hydroxybutyrate) in Vibrio natriegens / 生物工程学报

Accumulation of poly(3-hydroxybutyrate) [poly(3HB)] by V. natriegens was studied. Results indicated that V. natriegens used glucose, gluconate, fructose and molasses as carbon sources for poly(3HB) synthesis. When molasses was used, up to 28.4% of poly(3HB) to cellular dry weight was accumulated. The accumulation of poly(3HB) followed, was not simultaneously to, the cell growth. Analysis of the PHA polymerase, beta-ketothiolase, and acetoacetyl-CoA reductase showed that the poly(3HB) accumulation was correlated to the increase of their activities in cells. Poly(3HB) accumulation was also related to the de novo fatty acid synthesis, as revealed by the results that cerulenin, a specific inhibitor to the de novo fatty acid synthesis, significantly reduced accumulation of poly(3HB). Based on the results from this study, the synthetic pathway of poly(3HB) was proposed.

Survey on and Phytogeny of Alicyclobacillus Species in Hot Springs of Southern China's Guangdong and Yunna Provinces / 微生物学通报

12 isolates of thermoacidophilies were obtained from samples of hot springs of Southern China's Guangdong and Yunna provinces. All isolates are heterotrophic. Cells are rods, Gram positive or variable. The optimal pH and temperature for growth are 3.5-5.5 and 43℃-52℃, respectively. Based on their morphological physiological properties and their 16S rDNA sequences, they were identified as members of Alicyclobacillus.

BIOSYNTHESIS OF POLYHYDROXYALKANOATES BY RHODOCISTA PEKINGENSIS / 微生物学通报

In this article we report the results on the synthesis and accumulation of PHAs by Rhodocista pekingensis (strain 3-p), a phototroph that was isolated from wastewater treatment plant. Our results showed that the optimal conditions for PHAs accumulation with strain 3-p were as following: 0.01% Yeast Extract, 0.01% NH 4Cl, Acetate 5 g/L, and medium pH of 7.0～7.2.Under optimized conditions, strain 3-p accumulated PHAs up to 60% of its cellular dry weight. Enzymatic activities of ?-ketothiolase, acetoacetyl-CoA reductase, and PHA polymerase were detected and their activities increased as PHA synthesis initialized. Based on these study, we proposed the metabolic pathway of this strain should be:Acetate (or other fatty acids) - Acetyl-CoA --- thiolase Acetoacetyl-CoA --- reductase D (-)-?-Hydroxybutyryl-CoA ----- PHA polymerase PHAs.

BIOSYNTHESIS OF EMULSIEIER BY A NEWLY ISOLATED RHODOCOCCUS RUBER STRAIN Eml / 微生物学通报

A bacterial strain Eml isolated from contaminated soil of Shengli oil field was identified as Rhodococcus ruber according to its phenotype, physiological and chemical properties, and its 16S rRNA gene sequence. This strain could degrade various polycyclic aromatic hydrocarbons as well as alkanes in petroleum, and produce bioemulsifier. The results indicated that strain Eml could produce bioemulsifier efficiently when n-hexadecane was used as sole carbon source. The optimal conditions for the synthesis of bioemulsifier were as followed: 10g/L of n-hexadecane, 1g/L of yeast extract, media initial pH 7, and cultivation was carried out at 30℃ on a rotary shaker at 200 rpm. Under these conditions the surface tension of culture decreased to the lowest value, around 30 mN/m, after 1 day, and the emulsifying capacity was 100% . The concentration of bioemulsifier reached to the highest value, around 68 times of CMC , after 5 days' cultivation. The results also showed that the bioemulsifier produced by this strain should be lipid.