Development and testing of a 3D-printable polylactic acid device to optimize a water bioremediation process

Area of Science:

• Environmental Biotechnology
• Microalgal Bioremediation
• Biomaterials Engineering

Background:

• Polluted water bodies like the Matanza-Riachuelo watershed require effective remediation strategies.
• Immobilized microalgae show promise for water decontamination but face challenges with limited shelf life in natural environments.
• Polylactic acid (PLA) offers a biocompatible and biodegradable material for developing advanced bioreactor systems.

Purpose of the Study:

• To develop and evaluate a novel bioremediation bioprocess using Chlorella vulgaris immobilized in a 3D-printed polylactic acid (PLA) device.
• To assess the growth kinetics and bioremediation capacity of immobilized microalgae in confined systems (CfS) using polluted stream water.
• To determine the effectiveness of the PLA-confined microalgal system in reducing chemical and microbial contaminants.

Main Methods:

• Immobilization of native Chlorella vulgaris in alginate beads within a 3D-printed PLA device.
• Cultivation in Erlenmeyers and stirred-tank bioreactors using either Murashige Skoog (MS) medium or Cildáñez stream water.
• Comparison of unconfined systems (UcS) and confined systems (CfS) for growth kinetics and bioremediation efficiency.
• Analysis of inorganic nitrogen, total phosphorus, aerobic bacteria, and coliform levels.
• Cytotoxicity tests using Allium cepa seeds to evaluate decontamination effectiveness.

Main Results:

• The confined system (CfS) within the PLA device demonstrated successful bioremediation of Cildáñez stream water.
• Over 90% reduction in inorganic nitrogen and total phosphorus was achieved within 5 days.
• Approximately 85% decrease in aerobic mesophilic bacteria and a reduction in coliforms were observed.
• While growth parameters were optimal in MS medium (UcS), the CfS proved effective for actual water remediation.
• Cytotoxicity tests confirmed significant decontamination of the treated water.

Conclusions:

• The 3D-printed PLA device provides a stable and effective platform for immobilized Chlorella vulgaris bioremediation.
• The confined system (CfS) significantly enhances the removal of key pollutants from highly contaminated water.
• This approach offers a promising biotechnological solution for improving water quality in polluted watersheds.
• The use of biodegradable PLA aligns with sustainable environmental engineering practices.