Evaluation of Ligninolytic Enzymes Producing Aspergillus Aculeatinus B2819 for β-Lactam Antibiotics Bioremediation Potentials

A large quantity of antibiotics is consumed annually by humans and animals, generating corresponding antibiotic waste, primarily through feces and urine. The accumulation of antibiotic waste in the environment poses measurable health threats to humans and the environment. The biological method for removing antibiotic waste has been regarded as safe and environmentally friendly. β-Lactam antibiotics were used to simulate potato dextrose agar (PDA) to isolate fungi from sewage sludge. The fungal isolates were morphologically identified and screened for laccase and manganese peroxidase using Yeast extract dextrose – Copper sulphate (YPD – Cu) and Czapek-Dox media, respectively. The best fungal isolate was molecularly characterised. Thereafter, the removal efficiency of β-lactam antibiotics was assessed, and antibiotic residues were quantified by gas chromatography. The results showed varying morphological features among six fungal isolates (A1, A2, A3, A4, A5, and A6). Isolate A4 recorded the peak result (0.493 ± 0.0590 U/mL and 18.43 ± 2.5 U/mL) in both laccase and manganese peroxidase, respectively. Sample A4 was molecularly identified as Aspergillus aculeatinus B2819 and showed good remediation capacity of selected β-Lactam antibiotics (penicillin G, oxacillin, moxalactam, nocardicins, ampicillin and thienamycins). The percentage uptake of β-lactam antibiotics decreased as the initial antibiotic concentration increased from 0.042 mg/mL to 0.167 mg/mL. Although ampicillin was recorded as the most remediated antibiotic with 78.8 %, Aspergillus aculeatinus B2819 also gave outstanding antibiotic removal of penicillin G (76 %) and oxacillin (74 %). In summary, sewage was identified as a reservoir for β-lactam antibiotic-degrading fungi with improved laccase and manganese peroxidase production.