Molecular characterization of chromium tolerant and gelatin hydrolyzing

Overview

This source page is a mechanical bulk-ingest record for a PDF in the research-pulls corpus. It preserves source-level identity, routeable product/analyte scope, and exact extracted numeric lines for later human or fresh-context audit. It does not derive HMTc thresholds, percentiles, or brand-by-brand comparisons.

Key numbers

The worker extracted the full PDF text with layout preservation twice and compared extraction hashes before commit. The following lines are copied from numeric/table-bearing regions of the PDF and retain the source units and wording where legible:

• (MTC) range of 700 to 1500 ppm for Cr(III) and 200 to 600 ppm for Cr(VI). Physiological and biochemical
• to biodegrade hydrothermally treated CTLW at 98.67 %, 98.33 % and 98.00 %, respectively. The present study
• leather from Bangladesh experienced a significant growth of 30.95 % are actively functioning (3). However, the increasing worry over
• hides highly stable (6). Around 60–70 % of applied Cr salts undergo a identification of potential bacterial isolates. Finally, setting up a small
• (CTLW) accounts for about 35–40 % of solid wastes, typically containing the establishment of an optimal CTLW biodegradation approach utiliz­
• 3 % Cr2O3, 90 % collagen, and 7 % other impurities (4,8,9). The ing the potential bacterial species, consequently, recovery of Cr from the
• advantages. However, a permissible weekly dosage of 300 μg/kg of body tute (LRI) and stored at 4 ◦ C before analysis and during the experiments
• quefaciens (23,24), Bacillus cereus (25), Bacillus methylotrophicus (26), and 1 mL of H2O2 (30 %) was added to the sample. Following that, the
• was transferred in 9 mL of sterile 0.85 % saline water, and serial dilution described by Plestenjak et al. (50) with some modifications: the dena­
• the spread plate techniques as previously described (42–44) with products, the products were run through a 1.5 % agarose gel electro­
• modifications. The medium was amended with 100 ppm of Cr(III) using phoresis, stained with ethidium bromide, and visualized by a gel
• pure culture, labeled, and kept at 4 ◦ C in a refrigerator and also in 80 % Biotechnology Information’s (NCBI) Basic Local Alignment Search Tool
• 2.5. Evaluation of Cr tolerance for 24 h. From that broth culture 1 % v/v 30 mL overnight grown culture
• was prepared for each bacterial isolate. 0.3 g of dried CTLW (1 % w/v)
• modification. Cr-tolerant isolates were grown on Cr-incorporated media contamination. Autoclaved CTLW was taken in 1 % v/v inoculum cul­
• concentration of 100 ppm for each. Both positive and negative controls percentage was assessed for each isolate. Each experiment was repeated
• terium in a metal-supplemented medium was the negative control. % Degradation =.(Wi − Wd)/Wi × 100
• After removing the supernatant, the pellet was re-suspended in water 0.05) between means by using SPSS vs 25.0.
• rRNA gene (49). In a final volume of 40 µL, PCR reactions were carried Table 1 for DW, ECW, and CTLW. Temperature and pH were measured
• Table 1 reported for BI 8 with weak gas production ability. Sucrose fermentation
• Sample Physical parameter Metal concentration (ppm) by BI 3 and BI 8, as they were able to utilize urea as sole source of ni­
• BI 2 and BI 3 (Table 3). Identical results for biochemical tests such as
• sucrose and maltose without gas production (Table 3).
• around 21 ◦ C while the range of pH values was 7.52 to 7.93. DW con­
• tained the highest TDS concentration, accounting for 11,800 ppm. On
• (Table 3). Their carbohydrate fermentation pattern was also in a similar
• the largest concentration, which was precisely 2 ppm. The Cr concen­
• Visual observation of growth in Cr supplemented (100 ppm) NA 6).
• 3.3. Morphological and biochemical characterization The MTC of Cr(III) for BI 1, 2, and 5 was 700 ppm (Fig. 2 (A)), and for BI
• 3, it was 900 ppm (Fig. 2 (A)). BI 4 and 6 were reported to grow at the
• Bacterial isolates were characterized by morphological, cultural, maximum tolerance concentration of 1200 ppm Cr(III) (Fig. 2 (A)). The
• physiological, and biochemical properties. The colony morphology and MTC of Cr(III) for BI 7 and 8 was the highest, which was 1500 ppm
• isolates showed different morphological properties and growth patterns to 500 ppm (Fig. 2 (B)). BI 6 was found to have the MTC of Cr(VI) at 600
• in nutrient agar plate and nutrient agar slant, respectively. However, all Cr (Fig. 2 (B)). The MTC of Cr(VI) for BI 3, 8, and BI 5 was 250 ppm and
• (Fig. 1; a, b, c, e, f, and h respectively, and Table 3) were found as cocci tation system exhibited the 16S rRNA gene amplification by BI 4, BI 5,
• Table 3). Bacterial isolates 1, 3, 4, 5, 6, 7, and 8 were motile while BI 2 Using the forward and reverse primer, the PCR product was bi-
• was found as non-motile (Table 3). directionally sequenced. The sequences of BI 4, BI 5 and BI 7 have
• of 100 % for all of the bacterial isolates while a percent identity of 99.93 matter by measuring the loss of weight of the CTLW. Enterococcus fae­
• % for BI 4 and 100 % for both BI 5 and 7, respectively. The phylogenetic cium degraded the highest amount of CTLW, which was about 0.296 ±
• were identified as Bacillus wiedmannii (OR564007), Enterococcus faecium order of CTLW biodegradation percentage was 98.67 %>98.33 %>
• (OR564008), and Bacillus cereus (OR564009), respectively. Accession 98.00 % for Enterococcus faecium > Bacillus cereus > Bacillus wiedmannii,
• (54). The pH values ranged between 7.52 and 7.93 (Table 1). All of the

Methods (brief)

• isolated from the collected waste samples. The isolated bacteria showed the maximum tolerance concentration
• conducted for those isolates, which confirmed BI 4, 5, and 7 as Bacillus wiedmannii (Accession No: OR564007),
• biodegradation experiments showed that Enterococcus faecium, Bacillus cereus, and Bacillus wiedmannii were able
• demonstrates Enterococcus faecium, Bacillus cereus, and Bacillus wiedmannii having biodegradation of CTLW ap­
• specifically nitric oxide (10). Besides, CTLW is used as the principal 2.1. Study area and sample collection
• beings, including brain damage, lung disease, liver fibrosis, kidney collected from the chrome shavings landfill area, drain water (DW) was
• damage, neurotoxic effects, and even cancer (7,12). Cr(III), the main also collected from the drainage system of the same area, and effluent
• component of basic chromium sulfate is less hazardous than Cr(VI) (13). containing water (ECW) was collected from the surrounding regions of
• (14). European Food Safety Authority (EFSA) did not recommend the liquid and CTLW samples, respectively. The liquid samples were trans­
• hazardous issues and boost tannery output, an environmentally friendly 2.2. Physico-chemical analysis of liquid and solid samples
• collagen matrix must be removed, and this can be achieved by breaking using an inductively coupled plasma optical emission spectrometer (ICP-
• the bond between Cr and collagen through bacterial degradation of OES) (Model-5110 ICP-OES, Agilent). The total Cr content was deter­
• leather by protease activity such as gelatinase (17,18). Pretreatment like mined by digesting each sample using the microwave digestion pro­
• bacteria can utilize the produced gelatin as a substrate for their efficient In brief, for DW and ECW, 45 mL sample was taken within a 50 mL
• growth, and can be successful at degrading fibrous proteins including quartz digestion tube following the addition of 5 mL HNO3 (70 %) to the
• collagen, causing the degradation of CTLW, and liberating Cr in the sample. The containers were then sealed and subjected to a two-stage
• bacteria, including Bacillus subtilis (4,18), Alcaligenes faecalis (17), For CTLW, 0.2 g of fine particle (2 mm in size) sample was taken in a
• Lactobacillus strains (21), Enterococcus faecium (22), Bacillus amyloli­ quartz digestion tube with a capacity of 50 and 10 mL of HNO3 (70 %),

Implications

This page makes the source discoverable for category-level evidence routing. Values remain source-native and should be used only with the stated matrix, species, basis, geography, and censoring context from the paper. The page does not convert total mercury to methylmercury or use total arsenic as inorganic arsenic.

Wiki pages this source may touch

• Seaweed/kelp foods (nori, wakame, kombu, dulse — as food products)
• Chromium

Verification notes

• Identity check: DOI, raw handle, candidate cite-key, and SHA-256 were compared against existing wiki/sources/ pages before creation.
• Full-PDF read: pdftotext -layout was run on the full PDF twice; extracted text hashes matched before the page was written.
• Numeric verification: numeric/table-bearing lines were selected mechanically from the verified extraction and preserved without unit conversion or rounding.
• Brand firewall: the worker skips PDFs when extracted numeric lines appear brand/manufacturer-sensitive; this page contains category-level or species-level evidence only.
• HMTc firewall: no threshold, percentile, pass/fail, clean/dirty, or certification math is stated.

Update history

The five most recent substantive edits to this page, classified major (evidence or structure moved), correction (a published value or statement was wrong and has been fixed), or minor (narrative rewritten without changing the underlying evidence). Each description is derived from what the edit did to this page; the linked commit is the authoritative record, routine regeneration passes are excluded, and the full version history lives in git. When DOI minting comes online (see schema docs), each entry below will also link to a version-pinned DataCite DOI.