Investigation Report: "Screening of Alkaline Protease-Producing Marine Bacteria and Optimization of Fermentation Conditions" (Journal of Dalian Polytechnic University, 2014)

Academic fraud report · Geng Detector

Summary

This report assesses a 2014 paper by Song Mingzhu, Cong Lina, Wang Hongying, and Jiang Qichen on alkaline protease-producing marine bacteria (DOI: 10.19670/j.cnki.dlgydxxb.2014.042). The overall verdict is ⚠️ Questionable. The primary concern is that multiple single-factor optimization curves and enzymatic property curves (Fig. 1, Fig. 6, Fig. 7) display unnaturally perfect smoothness: a straight horizontal stability line at 100% relative activity between 25–40 °C, and overly idealized fermentation profiles resembling mathematical functions rather than experimental triplicate data. No error bars or point scatter are visible. A secondary limitation is severe text encoding corruption (likely GBK read as UTF-8), which precluded deeper numeric cross-checks such as last-digit distribution analysis. Confidence is moderate: findings rest on visual inspection of figures and the readable English abstract, while hidden methodological inconsistencies cannot be ruled out. The report does not claim definitive misconduct but flags the smoothness anomaly as warranting author response.

Verdict

⚠️ Questionable (Questionable / Suspect) — based primarily on visual irregularities in experimental figures; deeper numerical verification was constrained by text encoding issues.

Key findings

Multiple figures show textbook-perfect smoothness inconsistent with biological replicate variability.
Fig. 1 thermal stability curve appears as an exact horizontal line at 100% relative activity from 25–40 °C, with no error bars.
Fig. 6 (effect of initial pH on enzyme production) and Fig. 7 (effect of cultivation temperature on enzyme production) are described as overly smooth, resembling theoretical mathematical functions rather than fermentation-sample measurements.
The paper's full text contains severe encoding errors (GBK interpreted as UTF-8), limiting machine-based cross-validation of methods, reagent lot numbers, and numerical distributions.
No last-digit uniformity test or methods-logic check could be completed on the underlying numeric data.

Evidence highlights

Fig. 1 (Effect of temperature on enzyme activity and stability): The stability curve is rendered as an absolute straight horizontal line at 100% relative activity across 25–40 °C. There are no visible error bars or deviations typical of triplicate biochemical assays.
Fig. 6 (Effect of initial pH on enzyme production): Trajectory shows excessive smoothing, described as resembling a generated mathematical function.
Fig. 7 (Effect of cultivation temperature on enzyme production): Same smoothness concern as Fig. 6.
Full text: Contains garbled sequences such as µ°°×Ã¸ÊÇÔÚÒ»¶¨µÄ, indicating encoding-level corruption that blocks deeper automated checks.
DOI preserved: 10.19670/j.cnki.dlgydxxb.2014.042
Received date (inferred): 2014-01-12

Notes

The verdict is limited by the inability to recover the underlying numeric tables from the corrupted text; therefore, statistical tests (e.g., last-digit uniformity, Benford analysis) could not be performed.
The smoothness pattern alone does not prove fabrication — it may also reflect insufficient reporting of replicates, smoothed curve fitting without raw points, or plotting artifacts in the source PDF.
Readers are advised to treat specific quantitative claims from this paper with caution pending author clarification or institutional review.
A PubPeer-style query requesting raw replicate data and error-bar methodology would be a proportionate next step.
All findings were derived from visual figure inspection and the readable English abstract; conclusions beyond these sources would require re-extraction of clean text.