Lipase produced by Aspergillus is widely known and used in many industrial sectors. Three lipolytic filamentous fungi had been isolated from Kendari (Southeast Sulawesi, Indonesia) landfill soil in previous study and identified as Aspergillus niger KE1, Aspergillus terreus KC1, and Aspergillus fumigatus KE6. However, the optimization of these isolate has not been reported. In this study, statistical optimization is selected because of more effective, efficient, economical, robust in giving the results and the possibility of analysing the interaction effects among factors. Three lipolytic isolates were screened in initial medium to obtain the highest lipolytic isolate and it was used in medium optimization process. Optimization was done using the series experimental design of Taguchi and RSM. Optimization was sucessfully obtain the optimum medium with the reduction of medium component from previously medium reported. Aspergillus niger KE1 is the selected isolate with the highest lipase productivity after 72 h in initial medium. The significant factors affected lipase production are peptone, olive oil, glucose and MgSO4.7H2O. The model equation obtained is Y = 1043 – 228 A + 300 B – 19803 C + 99 A*A + 5720 B*B + 292855 C*C – 979 A*B + 6563 A*C – 56338 B*C. This model predicts the lipase productivity succesfully with R2 of 96.9%. The optimized medium composes of peptone 2%, olive oil 0.1%, glucose 0.5% and MgSO4.7H2O 0.075%. Using the medium, the lipase productivity increases 4.7-folds compared with before optimization. Our results suggest that Aspergillus niger KE1 is a potential lipase source which catalyse the esterification reaction. Further research is needed to purify and characterize the lipase enzyme of this isolate.

The present study was investigated the potential of lipolytic fungi (molds) isolated from landfill soil in degrading Poly-β-hydroxybutyrate (PHB). Screening of PHB-degrading lipolytic molds was done in two stages, such as screening of lipolytic molds which was identified by the formation of orange fluorescent halos around the colony on rhodamine B agar medium and the degradation PHB ability test was identified by the formation of clear zone around colony on PHB emulsion medium. Characterization of isolates was done based on phenotypic characters and the identification was done by numerical-phenetic analysis. Three lipolytic mold isolates that have ability in degrading PHB bioplastic i.e isolate KC1, KE1 and KE6. These molds have asexual spore form conidia, foot cell, septate hyphae, unbranched conidiophore, and spore mass located at the apex of phialid. The identification results showed that isolate KC1 is identic to Aspergillus terreus, KE1 is identic to Aspergillus niger and KE6 is identic to Aspergillus fumigatus.