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Four diesel fuel degrading microorganisms were isolated from soil and sea water from Crude Oil Terminal at Tianjin Port using diesel fuel as sole carbon source, and they all could degrade diesel fuel. The initial diesel fuel concentration in the culture medium was optimized and was 1.5 g/L. The ability of the four strains to degrade diesel was compared by spectrophotometer with the initial diesel concentration at 1.5 g/L. The results showed that the strain C1 had the highest degrading activity, which could degrade 32.59% of diesel in 7 days. The strain C1 was further identified by 16S rDNA sequence analysis as Rhodococcus erythropolis, and the phylogenetic tree of the strain C1 was constructed.

Two desulfurizing strains S1 and S2 were isolated from sea water from Crude Oil Terminal at Tianjin Port. The ability of the two strains to convert dibenzothiophene (DBT) to 2-dihydroxybiphenyl (HBP) was tested by Gibbs assay, which indicated that 2-HBP existed in the metabolite. The strains S1 and S2 were identified by both 16S rDNA sequence analysis and MALDI BioTyper system as Agrobacterium tumefaciens and Acinetobacter radioresistens respectively, which could degrade 22.3% and 22.4% of DBT in 46 hours respectively.

The open culture is a simple, low-cost way for microalage cultivation, and the great advantage of which is that it can be easily used for mass production. This culture system is primarily used for the alga that can survive under bad or extreme conditions. N. flagelliforme is a kind autotrophic alga having the property of alkali-resistance, which makes open culture of N. flagelliforme become possible. In this study, the cultivation of N.flagelliforme with an open, 60×40×30cm rectangular glass reactor was conducted. Firstly, the open culture of N.flagelliforme was carried on without new nutrient elements supplemented into pond intermittently. During the whole process of cultivation, the pH maintained at 8-9 in order to avoid the contamination of other green alga. At the end of the cultivation, the cell density reached 0.802 g•L-1 and the exopolysaccharide concentration was 97mg•L-1. Secondly, the fed-batch cultivation was employed to increase biomass and exopolysaccharide production. At the end of the fed-batch cultivation, the biomass and exopolysaccharide of N.flagelliforme increased distinctly to 1.16 g•L-1 and 124 mg•L-1, respectively.

Nostoc flagelliforme is a kind of terrestrial cyanobacterium with high economic value. Dissociated cells, which separated from a natural colony of N. flagelliforme, could be cultivated heterotrophically in the darkness on xylose and glucose under fed-batch culture conditions. Growth and extracellular polysaccharides (EPS) production in different cultures are investigated. At harvest time, the cultures contain 1.215 g•L-1 of biomass and 122.5 mg•L-1 of EPS respectively. The gravimetric EPS production rate is 17.5 mg•g-1•day-1, which is 1.65 times higher than previously reported results for heterotrophic Nostoc flagelliforme grown on xylose batch culture.