Ricky Rajamanickam, Chiampo Fulvia, Shanthakumar Subramaniam
Department of Environmental and Water Resources Engineering, School of Civil Engineering, Vellore Institute of Technology (VIT), Vellore 632014, India.
Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino, Italy.
Bioengineering (Basel). 2022 Mar 24;9(4):134. doi: 10.3390/bioengineering9040134.
Antibiotics are frequently detected in the aquatic environment due to their excessive usage and low-efficiency removal in wastewater treatment plants. This can provide the origin to the development of antibiotic-resistant genes in the microbial community, with considerable ecotoxicity to the environment. Among the antibiotics, the occurrence of ciprofloxacin (CIP) and amoxicillin (AMX) has been detected in various water matrices at different concentrations around the Earth. They are designated as emerging contaminants (ECs). Microalga () has been extensively employed in phycoremediation studies for its acclimatization property, non-target organisms for antibiotics, and the production of value-added bioproducts utilizing the nutrients from the wastewater. In this study, medium was spiked with 5 mg/L of CIP and AMX, and investigated for its growth-stimulating effects, antibiotic removal capabilities, and its effects on the biochemical composition of algal cells compared to the control medium for 7 days. The results demonstrated that adapted the antibiotic spiked medium and removed CIP (37 ± 2%) and AMX (25 ± 3%), respectively. The operating mechanisms were bioadsorption, followed by bioaccumulation, and biodegradation, with an increase in cell density up to 46 ± 3% (CIP) and 36 ± 4% (AMX), compared to the control medium. Further investigations revealed that, in the CIP stress-induced algal medium, an increase in major photosynthetic pigment chlorophyll-a (30%) and biochemical composition (lipids (50%), carbohydrates (32%), and proteins (65%)) was observed, respectively, compared to the control medium. In the AMX stress-induced algal medium, increases in chlorophyll-a (22%), lipids (46%), carbohydrates (45%), and proteins (49%) production were observed compared to the control medium. Comparing the two different stress conditions and considering that CIP is more toxic than AMX, this study provided insights on the photosynthetic activity and biochemical composition of during the stress conditions and the response of algae towards the specific antibiotic stress. The current study confirmed the ability of to adapt, bioadsorb, bioaccumulate, and biodegrade emerging contaminants. Moreover, the results showed that is not only able to remove CIP and AMX from the medium but also can increase the production of valuable biomass usable in the production of various bioproducts.
由于抗生素的过度使用以及污水处理厂中去除效率低下，在水生环境中经常能检测到抗生素。这可能成为微生物群落中抗生素抗性基因发展的源头，对环境具有相当大的生态毒性。在各种抗生素中，环丙沙星（CIP）和阿莫西林（AMX）在全球不同水体基质中均有不同浓度的检出。它们被认定为新兴污染物（ECs）。微藻（）因其适应性、对抗生素无靶向性以及能利用废水中的养分生产增值生物产品，已被广泛应用于藻类修复研究中。在本研究中，向培养基中添加5 mg/L的CIP和AMX，并与对照培养基相比，研究其对藻类生长的刺激作用、抗生素去除能力以及对藻细胞生化组成的影响，为期7天。结果表明，微藻适应了添加抗生素的培养基，分别去除了CIP（37 ± 2%）和AMX（25 ± 3%）。作用机制为生物吸附，随后是生物积累和生物降解，与对照培养基相比，细胞密度分别增加了46 ± 3%（CIP）和36 ± 4%（AMX）。进一步研究表明，与对照培养基相比，在CIP胁迫诱导的藻类培养基中，主要光合色素叶绿素-a增加了30%，生化组成（脂质（50%）、碳水化合物（32%）和蛋白质（65%））也分别增加。在AMX胁迫诱导的藻类培养基中，与对照培养基相比，叶绿素-a增加了22%，脂质增加了46%，碳水化合物增加了45%，蛋白质增加了49%。比较这两种不同的胁迫条件，并考虑到CIP比AMX毒性更大，本研究提供了关于胁迫条件下微藻的光合活性和生化组成以及藻类对特定抗生素胁迫的响应的见解。当前研究证实了微藻适应、生物吸附、生物积累和生物降解新兴污染物的能力。此外，结果表明微藻不仅能够从培养基中去除CIP和AMX，还能增加可用于生产各种生物产品的有价值生物质的产量。
