POTENTIAL OF NITRATE-REDUCING BACTERIA ISOLATED FROM X OIL FIELD SOUTH SUMATERA

• Main Author: RAVENA OKTAZIZAH (NIM : 10414036), GHINE
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/27505
• Institution: Institut Teknologi Bandung

<p align="justify">Nitrate injection into oil reservoir can prevent and remediate souring, the production of sulfide (S2-) by sulfate-reducing bacteria (SRB). Souring is a serious problem in oil industry since the production of S2- can lead to pipelines corrossion, decline in oil production rate and health risk. Nitrate injection stimulates the growth of nitrate-reducing bacteria (NRB) that outcompete SRB. Difficulty for the cultivation of NRB become a problem in the studying NRB. NRB is able to growth over a range of pH from 6,8 to 8,5, with an optimum temperature on 35&#8451;, the C/N ration of NRB range from 1-25, salt concentration up to 2% (w/v) and in anoxic environment. NRB is slow growth bacteria that require specific growth media and first inoculum density become an important factor that supports cell growth. This research aims to determine the optimum condition for nitrate-reducing bacteria in chemical defined media Widdel based on temperature, inoculum density percentage and carbon source; determine the effect of inoculum percentage (v/v) and carbon source on nitrate-reducing bacteria ability to reduce nitrate in chemical defined media Widdel. Nitrate-reducing bacteria consortia was anaerobically isolated from brine sample of oil field X South Sumatera using enrichment technique in chemical defined media Widdel, incubated in 37&#8451; and 50&#8451;. Optimum condition for NRB growth was determined by optimizing the number of initial bacterial inoculum of 5%, 10% and 15% (v/v), while carbon preference was determined by optimizing carbon source using xylene, n-hexan and toluene. Those hydrocarbon are commonly found in crude oil. Optimization was carried out for 84 hours at 37&#8451; by measuring bacterial density, pH, nitrate, nitite and ammonia content every 12 hours. Enrichment succeeded isolating the NRB in 37&#8451; which then subcultured and become inoculum. Inoculum age of NRB is 27 hours. Bacterial inoculum optimization shows that the growth pattern of NRB on 5%, 10% and 15% inoculum was not signiificantly different, logarithmic phase observed at 0-36 hours and stationary phase at 36-48 hours, but the highest NRB growth rate occured at 5% inoculum. NRB is able to use aromatic hydrocarbon and alkane, the growth rate of NRB on carbon sources toluene>n-hexane>xylene. NRB was able to assimilate sulfate during the logarithmic phase and the best sulfate reduction occured in the treatment of toluene. The best nitrate reduction ability was observed in the treatment of 5% inoculum administration, was 99.394% and the carbon source n-hexane was 57.966%. NRB isolates can grow well in the chemical defined media of Widdel at 37 &#8451;, initial inoculum 5% and using toluene as carbon sources. <br /> <p align="justify">