{"schema_version":1,"experiment_id":"eoa_inverse_innovation_exp06_four_proposal_generalization60_20260803","cell_id":"catalytic_pathway_enablement__chemistry_materials","arm":"COMPLETE_PROPOSAL_PORTFOLIO","candidate_id":"cpem_immobilized_enzyme_pet_fines_v0","proposal_index":1,"version":0,"title":"Regenerable Immobilized-Enzyme Basket for PET-Rich Textile Fines","problem":"At a textile-recycling pilot, a characterized stream of micronized PET-rich textile fines can be converted into specified soluble depolymerization products, but aqueous bond cleavage inside the permitted temperature and pH envelope occupies a reactor for too long. Increasing temperature or adding soluble enzyme introduces competing material-damage, separation, and enzyme-recovery burdens. The unresolved design problem is whether a selective enzyme immobilized in a removable reactor basket can lower the recurring kinetic barrier, release products without joining the output, and retain recoverable activity over multiple batches.","actors":["Pilot process owner","Reactor operators","Enzyme-immobilization technician","Analytical chemistry lead","Environmental health and safety reviewer","Downstream product-purification operator"],"observable_state":"For each batch, operators can observe feed identity and particle-size band, temperature, pH, basket occupancy, reaction time, PET conversion curve, target-product distribution, residual solids, transfer of dyes or additives, enzyme leaching, post-cycle catalyst activity, regeneration recovery, and downstream purification queue. The focal state is repeated slow conversion under an already authorized operating envelope, not an infeasible endpoint.","consequence":"Long reactor residence leaves the designated fines batch waiting or forces it onto an alternate disposition pathway; attempts to accelerate it without catalyst retention may add separation work, contaminate the product stream, or move the bottleneck into purification.","affected_objective":"Convert a defined PET-rich fines stream into products meeting the existing downstream specification with shorter catalyst-attributable cycle time, while preserving material accountability, product selectivity, operator safety, and downstream absorption capacity.","intervention":"Install a removable porous basket containing covalently immobilized, PET-active enzyme in a jacketed stirred bench reactor. Admit only homogenized feed within declared composition, particle-size, contaminant, pH, and temperature conditions. Run the batch for the minimum validated contact window, remove and rinse the basket, assay retained activity and leaching, then either return it to service, regenerate it by the authorized rinse and re-equilibration sequence, or retire it. Meter batches according to measured active capacity rather than nominal enzyme loading. Route incompatible feed and any batch showing unexpected products, excessive leaching, or analytical uncertainty to the existing non-catalytic evaluation path.","structural_mapping":[{"archetype_element":"Specified permitted transformation","domain_realization":"A characterized PET-rich textile-fines slurry becomes a defined distribution of soluble PET depolymerization products meeting the existing downstream assay; safety, composition, and product requirements remain unchanged."},{"archetype_element":"Recurring activation barrier","domain_realization":"PET bond cleavage at the permitted temperature and pH is hypothesized to be the repeated rate-limiting step, while recovering dispersed soluble enzyme would create a separate per-batch burden."},{"archetype_element":"Reusable facilitator","domain_realization":"PET-active enzyme is covalently retained on a porous removable basket, intended to contact successive batches without being consumed or released with product."},{"archetype_element":"Facilitator–substrate interface","domain_realization":"Feed particle size, solids loading, mixing, pH, temperature, contaminant limits, basket geometry, and contact time define how accessible polymer surfaces encounter immobilized active sites."},{"archetype_element":"Selectivity boundary","domain_realization":"The pathway targets PET-derived bonds in eligible feed while monitoring non-target polymer damage, dye or additive release, unintended soluble products, and enzyme leaching."},{"archetype_element":"Turnover capacity","domain_realization":"Useful conversions are counted per measured unit of retained enzyme activity, per batch and across sequential reuse cycles, alongside cycle time and activity loss."},{"archetype_element":"Saturation and interference control","domain_realization":"Solids loading, surface accessibility, basket occupancy, mixing behavior, product inhibition, and contaminant signals are tracked so excess feed is not mistaken for productive utilization."},{"archetype_element":"Regeneration and retirement","domain_realization":"The basket is rinsed, re-equilibrated, and reassayed after use; it is refreshed or retired when activity, selectivity, mechanical integrity, or enzyme-retention criteria are not restored."},{"archetype_element":"Equilibrium neutrality","domain_realization":"The enzyme is credited only with changing the rate or pathway distribution of an already achievable transformation, not with changing material balance, endpoint feasibility, product requirements, or authorization."},{"archetype_element":"Accountable stewardship","domain_realization":"The pilot process owner controls admission and loading, the analytical lead controls product and activity determinations, and the safety reviewer controls the operating envelope and restart after an incident."}],"mechanism_mapping":[{"mechanism_slug":"enzyme_or_biocatalyst","role":"Provides the selective, reusable active sites and defines the bounded temperature, pH, contact-time, and substrate-recognition envelope.","counterfactual_removal":"Without the enzyme, the basket is only an inert support; any observed acceleration would have to arise from mixing, adsorption, or another non-catalytic cause."},{"mechanism_slug":"heterogeneous_catalyst_bed","role":"Immobilizes enzyme on a removable porous basket so substrate passes active surfaces while the facilitator remains separable for reuse and regeneration.","counterfactual_removal":"Using dispersed enzyme would remove the retained-interface cycle and reintroduce per-batch enzyme separation, recovery, and product-contamination questions."},{"mechanism_slug":"interface_contract_design","role":"Declares feed composition, particle size, contaminant limits, operating conditions, output assay, release criteria, and exception routing.","counterfactual_removal":"Ill-prepared or incompatible feed could enter the reactor, making failures uninterpretable and allowing eligibility decisions to become discretionary."},{"mechanism_slug":"catalyst_cofactor_system","role":"Maps and checks required buffer capacity, water quality, mixing, temperature control, and any enzyme-required complement separately from the reusable enzyme.","counterfactual_removal":"A depleted or incompatible complement could make an intact basket appear deactivated, or hidden consumable inputs could be misattributed as catalytic leverage."},{"mechanism_slug":"inhibitor_and_poison_screen","role":"Screens feed and operating conditions for declared contaminants or additives that could reversibly inhibit or irreversibly deactivate the immobilized enzyme.","counterfactual_removal":"A contaminated batch could suppress multiple later cycles before declining activity is diagnosed, while unknown exclusions would remain unauditable."},{"mechanism_slug":"active_site_capacity_dashboard","role":"Displays basket identity, measured residual activity, current cycle, queue, cycle time, regeneration state, leaching trend, and downstream readiness.","counterfactual_removal":"Operators might load according to nominal enzyme mass or reactor availability even when active capacity is degraded or purification is already congested."},{"mechanism_slug":"catalyst_regeneration_protocol","role":"Defines the rinse, re-equilibration, reassay, return-to-service, refresh, and retirement decisions after each cycle.","counterfactual_removal":"Reuse would be nominal rather than demonstrated, and cumulative fouling or irreversible activity loss could remain hidden."},{"mechanism_slug":"turnover_and_selectivity_assay","role":"Compares successful conversion per retained activity unit, full product distribution, leaching, and degradation against no-enzyme, bare-support, and soluble-enzyme controls.","counterfactual_removal":"Faster mixing, adsorption, easier feed selection, or fresh-enzyme performance could be mislabeled as reusable catalytic effect."},{"mechanism_slug":"small_safe_to_fail_probe","role":"Bounds material, reactor volume, cycle count, operating conditions, and rollback while testing catalyst-on and catalyst-off conditions from one homogenized feed lot.","counterfactual_removal":"The basket could be adopted from a single favorable run without an attributable baseline, reuse evidence, or contained test of side pathways."}],"causal_chain":["A homogenized PET-rich fines lot is confirmed to satisfy the published feed and contaminant conditions.","Eligible slurry encounters immobilized enzyme under the authorized mixing, pH, temperature, and contact-time envelope.","Accessible PET surfaces bind at retained active sites, creating a lower-barrier reaction pathway than the matched catalyst-free condition is hypothesized to provide.","Specified soluble products are released into the liquid phase while the covalently retained enzyme remains on the basket.","Product and residual-solid assays distinguish target conversion from adsorption, non-target dissolution, dye or additive transfer, and enzyme leaching.","The basket is removed, rinsed, and assayed; recovered activity determines whether it returns to service, is regenerated, or is retired.","Successful target conversions are accumulated per retained activity unit across cycles, rather than counting raw batches or nominal enzyme mass.","Measured active capacity and downstream purification readiness constrain admission of the next batch.","Any selectivity, leaching, safety, integrity, or regeneration breach stops the catalytic path and returns material to containment or the established alternate evaluation path."],"baseline":"Use the same homogenized feed lot and authorized operating envelope in matched reactors containing no basket, a bare support basket, and a single-use soluble enzyme dose matched by initial measured activity. Compare time-resolved conversion, complete product distribution, mass balance, energy and buffer inputs, separation work, enzyme presence in product, and downstream assay acceptance. The immobilized route receives catalytic credit only for differences attributable to retained active enzyme and sustained through sequential reuse.","nearest_rivals":["Single-use soluble enzyme batch processing at matched initial activity, which may avoid immobilization mass-transfer limits but requires enzyme-product separation and does not demonstrate retained facilitator turnover.","Uncatalyzed or support-only aqueous treatment within the same authorized envelope, which tests whether mixing, adsorption, or residence time explains the result.","Higher-temperature, altered-pH, or reagent-driven depolymerization, which may accelerate conversion by adding bulk energy or consumable chemistry rather than by a reusable facilitator.","Improved feed milling, washing, or sorting, which may expose more PET surface or remove contaminants and could prove that feed preparation—not reaction activation—is the dominant barrier.","Additional reactor capacity, which addresses equipment congestion but does not increase transformation rate per active facilitator unit."],"remaining_contrastive_claim":"The proposal's remaining testable distinction is a closed facilitator cycle: retained enzyme must produce attributable acceleration with acceptable selectivity, separate from the output, recover activity after a defined restoration step, and repeat across batches. If performance depends only on a fresh enzyme dose, relaxed product criteria, greater bulk energy, easier feed, or added reactor capacity, the intervention is not supported as this catalytic-pathway design.","authority_safety":{"decision_authority":"The pilot process owner may authorize only the bounded bench trial after written concurrence from the environmental health and safety reviewer on operating and containment conditions and from the analytical lead on assays and predeclared decision criteria. Scale-up requires a separate decision.","authorized_first_step":"Characterize and homogenize one already-approved, nonhazardous PET-rich fines lot; qualify the immobilized basket for mechanical integrity and enzyme retention; then execute the bounded matched-control probe within the facility's existing bench-reactor envelope.","excluded_actions":["Processing unknown, hazardous, or screen-failing feed","Changing temperature, pressure, pH, reactor loading, or chemistry beyond the existing authorized bench envelope","Releasing trial products into production inventory or the environment","Weakening downstream product specifications or omitting the full product-distribution assay","Increasing feed rate to compensate for declining catalyst activity","Reusing a basket that fails activity, selectivity, leaching, or mechanical-integrity criteria","Scaling reactor volume, distributing baskets, or modifying production equipment under the pilot authorization"],"halt_rollback":"Stop heating and agitation using the approved reactor shutdown procedure; isolate the basket and liquid and solid fractions in labeled secondary containment; block all downstream release; preserve samples and logs; and route material through the facility's established characterization or disposal process. Restart requires the analytical lead to identify the deviation and the safety reviewer and process owner to approve a corrected protocol."},"negative_tests":{"strongest_counterevidence":"The strongest counterevidence would be comparable conversion in the bare-support control, substantial active enzyme in the product, or a sharp unrecoverable loss of activity after the first exposure. Those observations would indicate a mixing or adsorption effect, a consumed soluble reagent, or a non-reusable facilitator rather than the proposed catalytic cycle.","problem_falsifier":"The inferred problem is falsified if time-resolved mass balance shows that chemical bond cleavage is not the end-to-end rate-limiting burden—for example, if feed preparation, polymer-surface accessibility, analytical release, or downstream purification dominates cycle time even when fresh soluble enzyme is present—or if the specified endpoint is not achievable within the governing material and safety constraints.","intervention_falsifier":"The intervention is falsified if immobilized-enzyme runs do not reproducibly outperform both no-enzyme and bare-support controls on catalyst-attributable rate while meeting the unchanged product specification, or if sequential cycles fail predeclared activity recovery, enzyme-retention, selectivity, and mechanical-integrity criteria. Failure to distinguish saturation from deactivation also blocks continuation.","risks":["Immobilization may restrict substrate access enough to erase catalytic activity.","Fine particles may foul pores, shield active sites, or create nonuniform contact.","Dyes, finishes, metals, detergents, or other feed constituents may inhibit or poison the enzyme.","Enzyme or support fragments may leach into the product stream.","Selective PET cleavage may increase transfer of additives or produce an unacceptable soluble-product distribution.","Repeated rinsing may consume substantial buffer, water, energy, or labor and shift rather than lower the burden.","A favorable fresh-basket result may conceal rapid activity decay over reuse cycles.","Faster depolymerization may overload product purification, analysis, or residual-solids handling.","Tight feed eligibility may exclude difficult fractions and create misleading performance through selection.","A dashboard limited to measured signals may falsely reassure operators about unmeasured degradation modes."]},"next_evidence_step":"Run no more than 18 sealed 100-milliliter bench batches from one homogenized, previously approved feed lot. First, randomize triplicate runs among no-enzyme, bare-support, matched-activity soluble-enzyme, and fresh immobilized-enzyme conditions. Then pass the same immobilized basket through three additional feed batches, each paired with a bare-support control. Record conversion curves, full soluble-product distribution, residual-solid mass, enzyme leaching, pH, temperature, mixing state, buffer and wash use, basket integrity, post-cycle activity, activity recovered by regeneration, and downstream assay acceptance. Before starting, register acceptance and stop thresholds from the existing product specification, analytical detection limits, and safety envelope. Proceed only if the immobilized condition shows attributable acceleration, retains the unchanged quality boundary, and completes the reuse-regeneration cycles without a stop-triggering trend; otherwise contain the material and end the probe.","prior_art_status":"UNSEARCHED","diversity_from_prior_proposals":"Not assessed: this sealed task contains exactly one proposal and does not consult prior experiment candidates.","revision_record":{"parent_version":null,"progress_targets_addressed":[],"conceptual_changes":[],"operational_changes":[],"evidence_changes":[],"claim_changes":[]}}