APLIKASI BIOSURFAKTAN DARI BACILLUS LICHENIFORMIS F16 SEBAGAI AGEN BIOREMEDIASI TIMBAL PADA TANAH DENGAN PENDEKATAN SOIL WASHING

• Main Author: Ayu Lestari, Fauzia
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/78441
• Institution: Institut Teknologi Bandung

Soil pollution due to heavy metal Pb (lead) has occurred in various locations causing environmental problems. The toxicity of heavy metals depends on their fraction in environment. The management of heavy metal contaminated soil in Indonesia refers to Government Regulation Number 22 of 2021. The management stated can be performed by emerging remediation techniques, such as soil washing. Soil washing is an ex-situ bioremediation technique using washing agent which can be in the form of biosurfactant. Biosurfactant from bacterial isolat F16 which was identified as Bacillus licheniformis, at a concentration of 4.4 g/L has been reported to be capable of reducing 250 ppm Pb by 61% through soil washing. This research was conducted to observe the percentage of Pb removal trend of various Pb concentrations according to specified contamination limit, and its effect on the abundance of soil microbes which include actinomycetes, bacteria and fungi, as well as the effect on metal fractions distributions. Structural characterization of biosurfactants was also carried out to determine their mode of action in removing Pb. The research flow includes biosurfactant production and soil sample preparation. Pb polluted soil was prepared by mixing soil with Pb(NO3)2 at concentrations of 100, 500, and 2000 mg/kg. Metal levels in the soil were measured by Absorption Spectroscopy (AAS) and the effect on soil microbial abundance was observed. Metal fractions in the soil before and after soil washing were carried out using a sequential extraction method. The result showed that polluted soil changes the physical, chemical, and microbiological parameters of the soil. The abundance of soil microbes decreases after it is made contaminated. The abundance of soil microbe is decreasing after soil was made contaminated as the concentration of lead increased. After soil washing with biosurfactant, the removal percentages of 100, 500, and 2000 mg/kg Pb were 55.70 ± 5.87; 33.97 ± 3.86; and 5.60 ± 0.93%. The microbial abundance increased by 1-2 log cell numbers. Measurement of the Pb metal fraction showed that the metal fraction was dominated by oxide>residual>carbonate bound>exchangeable forms. After soil washing, there was a decrease in the abundance of the metal fraction. The results of structural characterization through FTIR and LC-MS showed that biosurfactants belong to the lipopeptide group with surfactin type. From this research, it is known that biosurfactant from Bacillus licheniformis F16 best removes low level category of Pb.