Population Dynamics within a Microbial Consortium during Diesel Wastewater Treatment

Six isolates obtained from diesel oil enrichment culture were reconstituted to form a mixed microbial consortium. And the biodegradation test of diesel oil was conducted at 28°C over 5 weeks. An antibiotic selection strategy was adopted to determine the magnitude of specific isolates and population dynamics within the mixed culture during diesel oil biodegradation. During biodegradation test, the amount of individual isolates has changed over the initial test density, and the proportion of individual isolates has changed heavily. From the initial of biodegradation test till to the fourth week of test, the isolates D1 and D2 were the most abundant in total culture. And from week 3 to week 5, isolates D5 and D6 increased continuously from 3% and 5% to 28% and 10% of total culture respectively. During the biodegradation test, the isolate D4 decreased continuously from 16.7% to 1% of the total culture by week 5; while isolate D3 decreased continuously from 16.7% of the total culture at the initial of test to below detection levels by week 5. At the end of biodegradation test, the isolates D2, D5 and D1 are the dominant microbial in total culture, and occupies 37%, 28% and 24% of total culture respectively. These dynamics of the culture respond directly to the residual components during biodegradation that available to be adopted as the growth substrates to microorganism.