Microbial Cr(VI) -> Cr(III) reduction in tannery/plating effluent

Provenanced sample report (Syntropa discovery, role-aware Stage-1). Corpus v0.2.2 (15,664 models, fingerprint 58a8f20e2aba) · tools v0.1.1 (git 44a8422, code a412618fd214) · env py3.13.13 win32 swiglpk5.0.13+osqp1.1.3+highspy1.15.1+pyscipopt6.2.1+optlang1.9.1 (deps 7f138ead8863). Feed=None target=None mode=produce. Report id 69371783b426 (content-addressed to config + EXACT corpus + EXACT tools -> auditable; git-reproducibility is PENDING a committed + tagged tool release). Every claim here is computed; every drop reason and known limit is listed below.

Verdict: NOT-EXPRESSIBLE

GAP TYPE = substrate present, product absent (the feedstock is modelable but the deliverable product has no corpus exchange). The Cr(VI) feedstock chromate ('cro4', 3299) is present as an exchange, but the reduction product Cr(III) is ABSENT from the corpus vocab: there is no 'cr3'/'cr' species (only 'cro4' and a single-model 'cro2'). Destroy-mode requires a vocab intermediate for biology's product, and Cr(III) has none; chromate appears only as an uptake, not a chromate-reductase reaction (same limitation as the chitin/GlcNAc case). MARKET DEMAND: Tanneries and electroplating shops pay to meet Cr(VI) discharge limits (~0.1 mg/L) and avoid fines (regulatory compliance).

Caveats (disclosed up front)

• PRODUCTION IS AN OPEN-MEDIUM UPPER BOUND, NOT A YIELD. The production flux is FBA on an OPEN medium: carbon and reductant may enter from the background medium, not only the named feed: so a value CAN EXCEED the feed-limited stoichiometric ceiling (e.g. CO2+H2->acetate <=~5 at 4 H2/acetate; glucose->CH4 <=~1 per glucose by the hydrogenotrophic route). Read every production number as an unconstrained UPPER BOUND; a value above the ceiling is an open-medium artifact, not an achievable closed-medium yield. Closed-medium re-runs are Phase-2.
• FBA proves a route is stoichiometrically POSSIBLE, not that a living cell will do it.
• Every consortium here is a HYPOTHESIS until cultured; nothing is wet-lab validated.
• MEMBER IDENTITY IS A LEAD, NOT A CLAIM. Named members are FBA-feasible only in AUTOMATED, GAP-FILLED DRAFT reconstructions: gap-filling can add transporters/reactions an organism does not actually have, so a named member may CONTRADICT established physiology (a strain the literature does not know to perform this chemistry). Check each named organism against the literature before treating it as a real candidate; the value here is the metabolic PATTERN, not the specific strain.
• Feedstock-dependence is the anti-medium-artifact control: withdraw the feed and the product must collapse (a NOT-feedstock-dependent result is flagged SUSPECT, not a discovery).
• The ranking score is a documented heuristic for human review, not a truth or biology claim.
• Stage-1 selects finisher x diverse front-ends; multi-finisher relays are out of scope. Stage-2 expansion of winners is pending: these are PRELIMINARY until it runs.