Development of a High-Throughput Fiber-Optic-Based Closed Bottle System for Evaluating the Ready Biodegradability of Water-Soluble Polymers

Water-soluble
polymers are widely used in various applications.
However, a large portion of them may end up in natural environments
after use and may pose a risk if they do not decompose naturally,
especially through biodegradation. Existing methods for evaluating
the ready biodegradability of water-soluble polymers are generally
costly, low throughput, and labor-intensive. To overcome such limitations,
this study developed a high-throughput method using a fiber-optic
dissolved oxygen measurement approach based on a modified OECD 301D
method. The new method was first compared with traditional methods
and showed similar biodegradation results. PolySeed was then evaluated
as an alternative inoculum to secondary effluent, and a strong correlation
was observed between the inoculum types, especially for highly biodegradable
substances (>60% of degradation). The investigation on the effect
of inoculum dosage suggested little difference among the three dosage
levels (0.05, 0.5, and 5 mL/L) within the recommended range by OECD
301D. Compared to smaller reactors (20 and 40 mL), only reactors with
volumes of 300 mL resulted in reasonable biodegradation. The further
evaluation of this new method on over 40 natural, synthetic, and graft
polymers indicated that it could be reliably applied for testing the
ready biodegradability of diverse water-soluble polymers.