Sludge oil contains 30%?50% hydrocarbon fractions that comprise saturated fractions, aromatics, resins, and
asphaltene. Asphaltene fraction is the most persistent fraction. In this research, the indigenous bacteria that can degrade
asphaltene fractions from a sludge oil sample from Balikpapan that was isolated using BHMS medium (Bushnell-Hass
Mineral Salt) with 0.01% (w/v) yeast extract, 2% (w/v) asphaltene extract, and 2% (w/v) sludge oil. The ability of the
four isolates to degrade asphaltene fractions was conducted by the biodegradation asphaltene fractions test using liquid
cultures in a BHMS medium with 0.01% (w/v) yeast extract and 2% (w/v) asphaltene extract as a carbon source. The
parameters measured during the process of biodegradation of asphaltene fractions include the quantification of Total
Petroleum Hydrocarbon (g), log total number of bacteria (CFU/ml), and pH. There are four bacteria (isolates 1, 2, 3, and
4) that have been characterized to degrade asphaltic fraction and have been identified as Bacillus sp. Lysinibacillus
fusiformes, Acinetobacter sp., and Mycobacterium sp., respectively. The results showed that the highest ability to
degrade asphaltene fractions is that of Bacillus sp. (isolate 1) and Lysinibacillus fusiformes (Isolate 2), with
biodegradation percentages of asphaltene fractions being 50% and 55%, respectively, and growth rate at the exponential
phase is 7.17x107 CFU/mL.days and 4.21x107 CFU/mL.days, respectively.
Isolasi Bakteri Pendegradasi Fraksi Aspaltik dari Lumpur Minyak Bumi. Lumpur minyak bumi mengandung
30%-50% fraksi hidrokarbon yang terdiri dari fraksi jenuh, aromatik, resin, dan aspaltik. Fraksi aspaltik merupakan
fraksi yang paling sulit didegradasi. Pada penelitian ini, bakteri pendegradasi fraksi aspaltik merupakan bakteri
indigenos yang diisolasi dari sampel lumpur minyak bumi di Balikpapan dengan menggunakan media Bushnell-Hass
Mineral Salt (BHMS) dengan 0.01% (b/v) ekstrak ragi, 2% (b/v) ekstrak fraksi aspaltik, dan 2% (b/v) lumpur minyak
bumi. Kemampuan isolat mendegradasi fraksi aspaltik diuji menggunakan media BHMS yang ditambahkan 0.01% (b/v)
ekstrak ragi dan 2% (b/v) ekstrak fraksi aspaltik sebagai sumber karbon. Selama uji biodegradasi dilakukan pengukuran
parameter yaitu Total Petroleum Hydrocarbon (g), jumlah total bakteri (CFU/mL), dan pH. Empat isoat bakteri (isolat
1,2,3, dan 4) yang telah dikarakterisasi mampu mendegradasi fraksi aspaltik dan teridentifikasi secara berurutan
sebagai, Acinetobacter sp., and Mycobacterium sp. Berdasarkan hasil penelitian, Bacillus sp. (isolat 1) dan
Lysinibacillus fusiformes (Isolat 2) memiliki kemampuan terbaik dalam mendegradasi fraksi aspaltik, kemampuan
biodegradasi fraksi aspaltik secara berurutan adalah 50% dan 55%, dan laju pertumbuhan pada fase eksponensial secara
berurutan adalah 7.17x107 CFU/mL.hari dan 4.21x107 CFU/mL.hari.
