MacConkey Agar Base - BioReagent

Cat. No.: M1528522

QUALITÄT & REINHEIT BioReagent

Storage

Room temperature

Shipped In

Normal

Übersicht

Carbohydrate-free, for fermentation studies of Escherichia coli

Spezifikationen

Spezifikationen & Reinheit

BioReagent

Storage

Room temperature

Verschickt in

Normal

Note

BioReagent

Product Line

Biologische Produkte

Application Protocols

The Product Data provide no specific protocols. The following is general, literature-based guidance for MacConkey-type media. Adjust to your SOPs and this item’s CoA.

Plate preparation (general):

• Suspend the recommended mass of dehydrated medium in purified water (typical working concentration ~50 g/L; verify per CoA).
• Heat with agitation to dissolve completely; bring to a brief boil if needed for clarity.
• Autoclave at 121 °C for ~15 min. Do not oversterilize.
• Cool to 45–50 °C, mix gently to homogenize dyes, and pour 20–25 mL per standard 90-mm plate. Let solidify; dry plates in a laminar flow cabinet if surface moisture is present.

Inoculation and incubation (general):

• Streak specimens for isolation or spread a measured volume for enumeration.
• Incubate plates inverted at 35–37 °C for 18–24 h (or per organism requirements).

Interpretation (general):

• Lactose fermenters: pink to red colonies, often with surrounding bile precipitate.
• Non-fermenters: colorless to pale colonies against the medium background.

Quality control (recommended practice):

• Include reference strains (e.g., E. coli as positive fermenter; Salmonella/Shigella spp. as non-fermenters; a Gram-positive control for inhibition). Exact strains and acceptance criteria should follow your laboratory SOPs.

Biological Roles

MacConkey Agar Base itself has no intrinsic biological role as a molecule; rather, it functions as a culture matrix engineered to exploit microbial physiology for selection and differentiation.

Mechanistic basis (general literature):

• Bile salts mimic intestinal conditions and disrupt Gram-positive cell envelopes, reducing their recovery while allowing bile-tolerant Gram-negative enterics to grow.
• Crystal violet further suppresses many Gram-positives by interfering with peptidoglycan-associated processes.
• Lactose (when present/supplemented) serves as a fermentable carbohydrate; organisms possessing β-galactosidase/ permeases metabolize it, generating acid.
• Neutral red is a pH indicator that becomes red/pink under acidic conditions, enabling differentiation of lactose fermenters via colony coloration and surrounding bile precipitate.
• Agar provides a non-nutritive gel network with minimal microbial metabolism, preserving colony integrity for observation.

Research implications:

• Facilitates studies of microbial ecology in enteric and environmental samples by enriching Gram-negative communities.
• Supports characterization of carbohydrate fermentation phenotypes, transport, and regulation in enteric bacteria.
• Serves as a platform for antimicrobial screening under selective stress (bile salts/dyes), though concentrations should be validated to avoid confounding toxicity.

Note: Specific component levels and performance characteristics for this item are not provided; consult the CoA/Spec Sheet for exact formulation and validation data.

Buffer Applications

This product is not a dedicated buffering agent or buffer system. While prepared MacConkey media exhibit a controlled pH (typically near neutral, literature), their buffering capacity arises incidentally from peptones and salts.

• If a defined buffer is required (e.g., for enzymology or electrophoresis), use established systems such as phosphate, Tris, HEPES, or MOPS.
• For culture work, adjust the medium pH only within the manufacturer’s recommended range to preserve selectivity and indicator function.

Item-specific buffer properties (pH range, buffering capacity): Not specified for this item; refer to CoA/Spec Sheet.

Green Alternatives

Green chemistry considerations are atypical for culture media, but sustainability and safety choices can still be made.

• Resource efficiency (general):

  • Right-sizing batch volumes minimizes waste from expired plates.
  • Use energy-efficient autoclave cycles and avoid unnecessary re-sterilization to reduce energy consumption.

• Component sourcing (general literature):

  • Where available, consider media that use plant-derived peptones instead of animal-derived digests to reduce animal-sourced inputs and potential variability.
  • Some laboratories favor chromogenic media that can consolidate multiple differential tests into a single plate, reducing overall material/energy use; however, these may introduce specialty dyes with different environmental profiles.

• Waste management:

  • Solid agar plates with biological growth must be autoclaved before disposal. After decontamination, segregate plastics (Petri dishes, packaging) for recycling programs where accepted.

Trade-offs:

• More selective media may include additional inhibitors/dyes with higher hazard classifications; balance selectivity needs with user exposure controls (ventilation, PPE).
• Lower agar concentrations reduce resource use but may compromise colony morphology and handling; maintain performance-driven concentrations.

Note: No item-specific eco-profile is provided in the Product Data. For facility-level sustainability, consult institutional EHS guidance.

Pharmaceutical Uses

No therapeutic or clinical uses are claimed. For research use only (per Product Data).

Relevant roles in pharmaceutical/biotech laboratories (general, non-clinical):

• Environmental monitoring and utilities testing: Recovery and differentiation of Gram-negative organisms from facility surfaces and water systems (where appropriate to research protocols).
• Raw material and in-process control microbiology: Isolation of Gram-negative contaminants during method development and training exercises.
• Antimicrobial effectiveness studies (research context): Supports qualitative assessments of Gram-negative recovery in the presence of experimental excipients or preservatives. Validate concentrations to avoid media–compound interactions.

Compliance notes:

• Where harmonized methods specify defined media compositions, verify conformance with the CoA/Spec Sheet or select media explicitly labeled for compendial methods. This item’s pharmacopeial status is Not specified in the Product Data.

Physical Properties

Item-specific physical property specifications are not provided in the Product Data for this dehydrated medium.

• Appearance: Not specified for this item; refer to CoA/Spec Sheet.
• Moisture content, pH of prepared medium, gel strength, and other QC attributes: Not specified for this item; refer to CoA/Spec Sheet.

General properties (literature, typical for MacConkey-type media; values may vary by manufacturer and lot):

• Form: Dehydrated, free-flowing powder blend containing agar and medium components.
• Color (dry): light beige to reddish-tan; Color (prepared): pink to red (due to neutral red/crystal violet).
• Reconstitution solvent: purified water.
• Typical working concentration: often around 50 g/L (literature). Final concentrations depend on manufacturer instructions.
• Typical pH (25 °C) of prepared medium: ~7.1 ± 0.2 (literature) before sterilization; pH can shift slightly after autoclaving.
• Gelation: solidifies on cooling (~40–45 °C) due to agar; melts above ~85 °C (literature for standard agar).
• Solubility: dehydrated powder disperses and dissolves upon heating in water; insoluble in organic solvents.
• Ionic strength/osmolality: determined by salts/peptones; varies with formulation (literature).

Practical notes (general):

• Use freshly prepared medium for optimal selectivity/differentiation; prolonged overheating can hydrolyze agar and fade indicators.
• Cloudiness or precipitation post-sterilization may indicate incomplete dissolution or water quality issues (e.g., high hardness).

Quality and Grades

• Item-specific grade from Product Data: BioReagent.

What BioReagent typically implies (general guidance):

• Intended use: Research and laboratory applications. Not for human or animal consumption, therapeutic, or diagnostic use.
• Quality expectations: Consistent performance in standard laboratory methods; may include growth promotion testing (GPT) for representative organisms, pH conformity of prepared medium, sterility testing, and physical attributes (appearance/clarity) — specifics vary by manufacturer and lot.

Growth promotion and performance (literature/industry practice):

• MacConkey-type media are commonly qualified using lactose-fermenting strains (e.g., Escherichia coli) and non-lactose-fermenters (e.g., Salmonella, Shigella or Pseudomonas) to verify selectivity and differentiation. Acceptance criteria include characteristic colony color/morphology and inhibition of Gram-positive controls.

Stabilizers and supplements:

• Some “Agar Base” formulations are designed to be supplemented (e.g., with lactose or specific carbohydrates, antibiotics, or selective agents). The presence/absence of these is manufacturer-specific. For this item, composition and any required supplements are Not specified; refer to CoA/Spec Sheet.

Documentation:

• For regulated or critical applications, request the CoA/Spec Sheet for this exact lot to confirm pH targets, fill weights, recommended reconstitution, GPT organisms, and any compliance notes (e.g., conformance to harmonized pharmacopeial recipes when applicable).

Reaction and Applications

This product is not a chemical reagent for synthetic reactions. Instead, its applications are in microbiology as a selective and differential culture medium.

Microbiological applications (general literature):

• Selective isolation of Gram-negative enteric bacteria: Bile salts and crystal violet inhibit Gram-positive organisms, enriching for Enterobacteriaceae and related Gram-negative rods.
• Differentiation by lactose fermentation: Neutral red indicates acid production. Lactose-fermenters (e.g., typical E. coli, Klebsiella) produce pink to red colonies, often with a precipitated bile halo; non-fermenters (e.g., Salmonella, Shigella, Proteus) remain colorless to pale.
• Enumeration and subculture: Useful for colony counts, purity checks, and isolation from mixed samples in environmental, food, and industrial microbiology research.
• Supplementation flexibility: "Agar Base" may be supplemented (e.g., with lactose, sorbitol, or antibiotics) to tailor selectivity or target phenotypes; verify with the specific product CoA for required supplements.

Practical tips (general):

• Prepare plates at recommended concentration; over- or under-gelling can alter diffusion of inhibitors and indicators.
• Avoid overheating during sterilization; prolonged autoclaving can reduce dye intensity and alter selectivity.
• Dry plates (lid ajar in a laminar flow cabinet) before use to prevent colony spreading.
• Perform growth promotion testing on new lots with representative organisms to confirm expected selectivity/differentiation for your application.

Reaction Conditions

Not applicable to chemical reactions. However, for culture preparation (general literature guidance):

• Solvent: Purified water.
• Dissolution: Heat with stirring to boiling until the powder fully dissolves and the solution is uniform.
• Sterilization: Autoclave at 121 °C for ~15 minutes (liquid cycle). Avoid oversterilization to preserve indicator performance.
• Pouring temperature: Cool to ~45–50 °C before pouring plates to prevent condensation and dye precipitation.
• Incubation (post-inoculation): Commonly 35–37 °C, 18–24 h (organism-dependent). Adjust per experimental design.

All parameters above are general literature values for MacConkey-type media; item-specific instructions are Not specified for this item; refer to CoA/Spec Sheet.

Safety and Handling

Safety details specific to this item (GHS classification, H-statements, pictograms) are not provided in the Product Data. Always consult the product SDS for authoritative, item-specific guidance.

General laboratory safety guidance for dehydrated culture media (literature/practice-based):

• Hazard overview: Complex mixtures may cause eye/skin/respiratory irritation due to dyes (e.g., crystal violet), bile salts, and fine particulates. Avoid dust formation and inhalation.
• PPE: Lab coat, safety glasses or splash goggles, appropriate gloves (e.g., nitrile). Use a dust mask/respirator if handling large quantities or if dust cannot be controlled (per institutional risk assessment).
• Engineering controls: Handle powders in a well-ventilated area; use a balance enclosure or fume hood to minimize dust exposure.
• Hygiene: Wash hands thoroughly after use. Do not eat, drink, or smoke in areas where media are handled.
• Incompatibilities (general): Strong oxidizers and strong acids/bases may degrade organic components and dyes. Avoid moisture uptake; store tightly closed.
• Thermal processing: During autoclaving, do not seal containers tightly; allow steam venting to prevent pressure buildup. Avoid overheating/oversterilization that can darken media and reduce performance.
• Biological risk management: After inoculation, media become biohazardous. Autoclave all used plates/broths and contaminated disposables at 121 °C for ≥15–20 min (or per facility SOP) before disposal.
• First aid (overview): If inhaled, move to fresh air; for eye/skin contact, rinse with water; if ingested, rinse mouth. Seek medical attention if irritation persists. Defer to SDS for detailed measures.

Solvent Selection

This product is a dehydrated culture medium; it is not used as a reaction solvent. Solvent considerations are limited to correct reconstitution for microbiology use.

• Primary solvent (applicable):
  • Purified water (e.g., ASTM Type II or better). Avoid high hardness or high organic carbon that can cause haze or inhibit growth.
• Practical guidance (general literature):
  • Heat with agitation to fully dissolve agar and distribute bile salts and dyes. Boiling is often required prior to sterilization to ensure clarity.
  • Do not use organic solvents; they will not dissolve agar and can precipitate components or inhibit microbial growth.
• Water quality comparisons (general):
  • Deionized/distilled water: Preferred for consistency of selectivity/indicator performance.
  • Tap water: Not recommended due to variable ions (Ca2+/Mg2+) and chlorine/chloramine, which can affect gelation and microbial recovery.

When to choose MacConkey Agar Base versus alternatives (general):

• Select MacConkey formulations when a selective/differential medium for Gram-negative enterics is desired. Consider alternatives like EMB agar (Eosin Methylene Blue) for stronger differentiation of E. coli, or Hektoen enteric agar for Salmonella/Shigella-focused recovery, depending on research needs.

Storage and Reconstitution

Item-specific storage from Product Data:

• Storage conditions (dehydrated): Room temperature. Keep container tightly closed in a cool, dry place.
• Shipped: Normal conditions.

Additional best practices (general):

• Protect from moisture uptake and light to preserve indicator dyes. Use desiccant where appropriate.
• Record opening date and manage by first-in/first-out to maintain performance.

Reconstitution and sterilization (literature/general guidance; confirm with CoA/SDS):

• Water quality: Use purified/deionized water.
• Concentration: Typical working concentration is around 50 g/L; confirm the exact value for this item on the CoA/label.
• Dissolution: Heat with stirring to achieve complete dissolution and clarity; avoid scorching.
• Sterilization: Autoclave at 121 °C for ~15 minutes. Do not oversterilize to prevent indicator degradation.
• Post-sterilization handling: Cool to 45–50 °C before pouring to minimize condensation and color artifacts. Gently mix to maintain homogeneity of inhibitors/indicators.
• Storage of prepared plates: If not used immediately, store inverted in sealed bags/containers at 2–8 °C to limit dehydration and dye fading; typical in-lab shelf life is limited and should be defined by internal QC.

Re-use and stability:

• Avoid repeated melting/solidification cycles; each cycle can reduce gel strength and alter selectivity.

Research use note: For research use only (per Product Data).

Structure and Identity

This product is a dehydrated complex microbiological medium, not a single defined chemical compound.

• Item-specific identifiers from Product Data:

  • Product name: MacConkey Agar Base (SKU: M1528522)
  • Grade/Purity: BioReagent
  • CAS: Not specified for this item; refer to CoA/Spec Sheet.
  • Molecular formula: Not applicable (complex mixture)
  • Molecular weight: Not applicable (complex mixture)
  • SMILES / InChI / InChIKey: Not applicable (mixture)

• Structural description (general literature):

  • MacConkey Agar Base is a mixture typically containing peptones/peptic digest and pancreatic digest of casein, bile salts, sodium chloride, crystal violet, neutral red (indicator), and agar as the gelling agent. “Base” formulations may be intended for supplementation (e.g., addition of lactose) depending on manufacturer; verify the specific formulation in the CoA.
  • As a heterogeneous blend, it possesses no single 2D molecular structure; rather, it is a composite of small-molecule dyes/indicators, bile salt surfactants, inorganic salts, and high–molecular-weight agarose/agalactan polysaccharides.

• Functional features (general literature):

  • Selective agents: bile salts and crystal violet inhibit Gram-positive bacteria.
  • Differential system: neutral red indicator reports acid production from lactose fermentation, yielding pink to red colonies in lactose-positive organisms.
  • Solidifying matrix: agar supports colony morphology and isolation.

Synthetic Utility

Not applicable. MacConkey Agar Base is a microbiological culture medium and is not used as a reagent or building block in synthetic organic, inorganic, or materials chemistry.

For chemical synthesis, refer instead to solvent/reagent sections of the catalog. For this product, see the sections on Reaction & Applications (microbiological), Application Protocols, and Storage & Reconstitution for practical laboratory use.

Target Specificity

This product is not an antibody or affinity reagent. No antigen/epitope specificity, clone information, or species reactivity applies.

Functional selectivity (general literature):

• Selects for Gram-negative, bile-tolerant bacteria and differentiates lactose fermenters from non-fermenters via a pH indicator system.

Item-specific target details: Not specified for this item; refer to CoA/Spec Sheet.