Bacterial Cell Wall Degradation Technology

Bacterial cell wall degradation is a key technique that disrupts peptidoglycan and its outer structures through enzymatic, chemical, or physically assisted methods, allowing cellular contents to be released or enabling the formation of protoplasts/spheroplasts. This technology is commonly used for DNA/RNA extraction, protein release, cell wall component analysis, bacterial identification, antibacterial mechanism research, and evaluation of cell wall synthesis inhibitors.

Keywords: bacterial cell wall; peptidoglycan; lysozyme; lysostaphin; EDTA; SDS; Proteinase K; cell lysis; protoplast; Gram-positive bacteria; Gram-negative bacteria

1 Technical Positioning of Bacterial Cell Wall Degradation

1.1 Cell Wall Structure Determines Lysis Difficulty

The main scaffold of the bacterial cell wall is peptidoglycan, which is composed of alternating N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM) sugar chains, with short peptide crosslinks maintaining mechanical strength. The outer cell wall structures of different bacterial groups differ markedly, so the same lysis method may show completely different effects in different bacteria.

Bacterial Type	Structural Characteristics	Degradation Difficulty	Common Strategy
Gram-positive bacteria	Thick peptidoglycan layer, often containing teichoic acids	Thick peptidoglycan limits cellular content release	Lysozyme, lysostaphin, mutanolysin, mechanical assistance
Gram-negative bacteria	Thin peptidoglycan layer, with an outer membrane and LPS	Outer membrane blocks enzyme entry	EDTA, mild surfactants, combined lysozyme treatment
Staphylococci	Strong peptidoglycan crosslinking, with pentaglycine bridges	Conventional lysozyme is often insufficient	Lysostaphin is more suitable
Streptococci/lactic acid bacteria	Complex peptidoglycan and surface polysaccharides	Relatively strong cell wall stability	Mutanolysin and lysozyme combinations
Mycobacterium-like cell walls	Rich in lipids and waxy structures	Strong hydrophobic barrier and poor enzyme entry	Chemical pretreatment, mechanical disruption, specialized lysis systems
Spores	Dense outer structures and high resistance	Enzymes are difficult to directly access the core structure	Pretreatment followed by enzymatic digestion or mechanical disruption

1.2 Degradation Goal Does Not Equal Complete Lysis

The method selected for bacterial cell wall degradation depends on the experimental purpose. If the goal is nucleic acid or protein extraction, release efficiency is usually the main concern. If the goal is cell wall structure analysis, excessive disruption should be avoided. If the goal is protoplast or spheroplast preparation, the degree of degradation must be controlled under isotonic conditions to prevent immediate osmotic lysis.

Experimental Purpose	Technical Focus	Method Selection
DNA/RNA extraction	Improve lysis efficiency and reduce nucleic acid degradation	Enzymatic digestion + lysis buffer + protease treatment
Protein extraction	Preserve protein activity or modification status	Mild enzymatic digestion, low-temperature lysis, protease inhibition
Protoplast/spheroplast preparation	Control the degree of cell wall degradation	Enzymatic digestion + isotonic protection
Cell wall component analysis	Preserve peptidoglycan fragment information	Targeted enzymatic digestion and avoidance of strong disruption
Antibacterial mechanism research	Determine changes in cell wall integrity	Fluorescent staining, morphological observation, lysis sensitivity detection
Auxiliary bacterial identification	Distinguish differences in cell wall sensitivity	Specific enzyme treatment combined with microscopy or molecular detection

2 Main Degradation Targets in the Bacterial Cell Wall

2.1 Peptidoglycan Glycosidic Bonds

Peptidoglycan glycan chains are formed by NAG and NAM connected through β-1,4 glycosidic bonds. Lysozyme mainly hydrolyzes this glycosidic bond, causing the peptidoglycan scaffold to break. It is one of the most commonly used cell wall-degrading enzymes.

Glycosidic bond degradation is suitable for basic lysis of many bacteria. However, for thick-walled Gram-positive bacteria, staphylococci, or strains with extensive cell wall modifications, lysozyme alone may be insufficient. In such cases, lysostaphin, mutanolysin, EDTA, SDS, or mechanical disruption may be combined to improve lysis efficiency.

2.2 Peptide Bridges and Crosslinking Structures

Peptidoglycan crosslinking structures determine cell wall strength. In staphylococci, pentaglycine crosslinking bridges are common. Lysostaphin can specifically cleave this structure, making it more targeted for Staphylococcus aureus, Staphylococcus epidermidis, and other staphylococcal bacteria.

The value of this type of enzyme lies in its strong selectivity. It is suitable for treating Gram-positive cocci that are not easily lysed by conventional lysozyme. However, it should not be simply generalized to all bacteria. In experimental design, whether the target bacterium has a matching cell wall crosslinking structure should be determined first.

2.3 Outer Membrane Barrier of Gram-Negative Bacteria

Gram-negative bacteria have a thin peptidoglycan layer, but their outer membrane and lipopolysaccharide prevent large molecules such as lysozyme from directly contacting peptidoglycan. Therefore, the key to cell wall degradation in Gram-negative bacteria is not the peptidoglycan itself, but first weakening the outer membrane barrier.

A common approach is to use EDTA to chelate divalent cations such as Mg²⁺ and Ca²⁺, weaken outer membrane stability, and then combine this with lysozyme or lysis buffer. Without outer membrane pretreatment, lysozyme usually has limited lysis efficiency against Gram-negative bacteria.

3 Common Cell Wall Degradation Methods

3.1 Lysozyme Degradation

(1) Mechanism of action

Lysozyme mainly hydrolyzes the β-1,4 glycosidic bond between NAG and NAM in peptidoglycan, loosening the cell wall scaffold. After cell wall strength decreases, cells are more easily lysed with assistance from hypotonic conditions, surfactants, or mechanical action.

(2) Applicable scenarios

Lysozyme is commonly used for bacterial nucleic acid extraction, protein extraction, pre-lysis of Gram-positive bacteria, enhanced lysis of Gram-negative bacteria after outer membrane treatment, and some cell wall sensitivity experiments. It is the most basic and broadly applicable bacterial cell wall-degrading enzyme.

(3) Technical advantages

Lysozyme conditions are mild and relatively friendly to nucleic acids and most proteins. It is suitable for use with Proteinase K, SDS, Triton X-100, EDTA, and other components. For samples requiring preservation of nucleic acid integrity or protein activity, lysozyme is milder than strong mechanical disruption.

(4) Limitations and risks

Lysozyme is not a universal cell disruption solution for all bacteria. Staphylococci, some streptococci, lactic acid bacteria, spore-associated samples, and strains with strong cell wall modifications may be insensitive to lysozyme. Insufficient lysis can lead to low DNA yield, low protein recovery, or obvious bacterial residue.

3.2 Lysostaphin Degradation

(1) Mechanism of action

Lysostaphin mainly cleaves the pentaglycine crosslinking bridges in staphylococcal peptidoglycan, disrupting the cell wall crosslinking structure. Compared with lysozyme, it is more targeted toward staphylococcal bacteria.

(2) Applicable scenarios

Lysostaphin is suitable for staphylococcal lysis, staphylococcal DNA/RNA extraction, protein release, rapid bacterial lysis verification, and antibacterial mechanism research. For samples such as Staphylococcus aureus and Staphylococcus epidermidis that are insufficiently lysed by conventional lysozyme, lysostaphin is usually more effective.

(3) Technical advantages

The greatest advantage of this enzyme is its strong specificity, which can significantly improve lysis efficiency for staphylococcal samples. In molecular detection, it can reduce false-negative or low-recovery problems caused by insufficient cell wall lysis.

(4) Limitations and risks

Lysostaphin is not suitable for all Gram-positive bacteria. Its effect depends on specific peptide bridge structures. If the target bacterium does not contain the corresponding crosslinking form, the effect will be markedly reduced. Therefore, it should not be described as a broad-spectrum bacterial cell wall-degrading enzyme in experimental protocols.

3.3 Mutanolysin Degradation

(1) Mechanism of action

Mutanolysin is a type of cell wall hydrolase that acts on the peptidoglycan of Gram-positive bacteria. It is commonly used to lyse streptococci, lactic acid bacteria, and some Gram-positive bacteria with difficult-to-process cell walls.

(2) Applicable scenarios

Mutanolysin is suitable for cell wall degradation in streptococci, lactic acid bacteria, some anaerobic Gram-positive bacteria, and oral microbiome samples. It is often used for microbiome sample pretreatment, nucleic acid extraction, and improvement of Gram-positive bacterial lysis efficiency.

(3) Technical advantages

Mutanolysin can compensate for insufficient lysis of certain Gram-positive bacteria by lysozyme alone. For mixed microbial community samples, adding mutanolysin can improve nucleic acid release efficiency from thick-walled or difficult-to-lyse bacteria and reduce species detection bias.

(4) Limitations and risks

Mutanolysin still needs to be optimized according to bacterial species and sample type. Overemphasizing its broad-spectrum nature is inaccurate. It is more suitable for specific Gram-positive bacterial groups, rather than all bacterial lysis scenarios.

3.4 EDTA-Assisted Outer Membrane Permeabilization

(1) Mechanism of action

The outer membrane of Gram-negative bacteria contains lipopolysaccharide and divalent cation-stabilized structures. EDTA can chelate Mg²⁺, Ca²⁺, and other ions, weakening outer membrane stability and allowing lysozyme or other lysis components to more easily access the peptidoglycan layer.

(2) Applicable scenarios

This strategy is suitable for pretreatment before lysis of Gram-negative bacteria such as Escherichia coli, Salmonella, and Pseudomonas aeruginosa. It is also applicable to plasmid extraction, lysis of protein expression bacteria, and outer membrane integrity studies.

(3) Technical advantages

Outer membrane permeabilization can significantly improve lysozyme efficiency against Gram-negative bacteria. Compared with strong mechanical disruption, EDTA-assisted enzymatic lysis is milder and suitable for experiments requiring preservation of nucleic acid integrity or protein activity.

(4) Limitations and risks

EDTA may affect the activity of metal-dependent enzymes and may also interfere with some downstream enzymatic reactions. If downstream applications involve metal ion-dependent enzymatic assays, buffer exchange or removal of residual EDTA is required after lysis.

3.5 Surfactant and Chemical Lysis Assistance

(1) Mechanism of action

Surfactants such as SDS, Triton X-100, and Tween-20 can disturb cell membrane structures and help release intracellular components. They usually do not directly or specifically cleave peptidoglycan, but instead promote membrane lysis and protein solubilization after cell wall enzymatic degradation.

(2) Applicable scenarios

SDS is commonly used for nucleic acid extraction and total protein lysis. Triton X-100 is suitable for relatively mild membrane permeabilization and protein release. Tween-20 is mostly used for washing and mild assistance. For bacterial samples, surfactants usually serve as lysis-enhancing components after enzymatic digestion.

(3) Technical advantages

Chemical lysis assistance can improve content release efficiency and shorten lysis time. For nucleic acid extraction, SDS combined with Proteinase K can help disrupt membrane structures, denature proteins, and release DNA/RNA.

(4) Limitations and risks

SDS strongly denatures proteins and is not suitable for experiments requiring preservation of protein activity. Surfactant residues may also affect PCR, enzyme activity assays, mass spectrometry, or protein interaction experiments. Therefore, mild or strong lysis systems should be selected according to downstream applications.

3.6 Mechanical Disruption Assistance

(1) Mechanism of action

Mechanical disruption directly applies physical shear forces through grinding, bead beating, sonication, high-pressure homogenization, and other methods to rupture the cell wall and cell membrane. It does not depend on specific enzymatic recognition sites, so it has strong applicability for difficult-to-lyse bacteria and complex samples.

(2) Applicable scenarios

Mechanical disruption is suitable for difficult-to-lyse bacteria, spore samples, complex microbial samples such as soil, feces, and biofilms, and experiments requiring maximal release of total nucleic acids or total proteins.

(3) Technical advantages

Mechanical methods have strong broad-spectrum applicability and can reduce lysis bias caused by differences in bacterial cell wall structures. For metagenomics, microbial community analysis, and environmental microbial detection, mechanical disruption is often used to improve lysis coverage.

(4) Limitations and risks

Mechanical disruption can easily cause DNA fragmentation, protein denaturation, sample heating, and aerosol risk. If the goal is long-fragment DNA, active proteins, or mild protoplast preparation, mechanical disruption should not be the first-choice method.

4 Cell Wall Degradation Strategies for Different Samples

4.1 Gram-Positive Bacteria

Gram-positive bacteria have a thick peptidoglycan layer, and simple chemical lysis is often insufficient. The routine strategy is to first use cell wall hydrolases to weaken peptidoglycan, and then combine surfactants, proteases, or mechanical assistance to complete lysis. Lysostaphin should be prioritized for staphylococci, while mutanolysin or combined enzyme treatment can be considered for streptococci and lactic acid bacteria.

4.2 Gram-Negative Bacteria

The key to Gram-negative bacterial lysis is outer membrane treatment. EDTA, osmotic changes, and mild surfactants can weaken the outer membrane barrier, allowing lysozyme to contact the peptidoglycan layer. For routine molecular biology experiments, Gram-negative bacteria are usually easier to lyse than thick-walled Gram-positive bacteria.

4.3 Mixed Microbial Community Samples

Fecal, soil, biofilm, and oral samples often contain Gram-positive bacteria, Gram-negative bacteria, and difficult-to-lyse bacteria simultaneously. If only a single enzymatic condition is used, some bacteria may be insufficiently lysed, affecting microbial community composition analysis. Mixed samples are more suitable for combined strategies involving multiple enzymes, mechanical disruption, and lysis buffers.

4.4 Biofilm Samples

Biofilms contain not only cell wall barriers, but also extracellular matrices composed of polysaccharides, proteins, DNA, and lipids. When processing biofilm samples, cell wall degradation alone is usually insufficient. The extracellular matrix also needs to be disrupted to improve the access of enzymes and lysis reagents to bacterial cells.

Sample Type	Main Difficulty	Recommended Strategy
Common Gram-negative bacteria	Outer membrane blocks enzyme entry	EDTA assistance + lysozyme + lysis buffer
Thick-walled Gram-positive bacteria	Thick peptidoglycan layer	Lysozyme/mutanolysin + mechanical or chemical assistance
Staphylococci	Pentaglycine crosslinking bridges	Lysostaphin first
Streptococci/lactic acid bacteria	Relatively stable cell wall structure	Mutanolysin or combined enzymes
Mixed microbial communities	Differences in lysis efficiency among bacterial species	Combined enzymes + mechanical disruption to reduce bias
Biofilms	Extracellular matrix blocks access	Matrix disruption + cell wall degradation + lysis buffer

5 Method Selection for Downstream Applications

5.1 Nucleic Acid Extraction

Nucleic acid extraction requires sufficient cell wall lysis while minimizing DNA/RNA degradation. In Gram-positive bacteria and mixed microbial community samples, insufficient cell wall degradation directly leads to low nucleic acid recovery and detection bias. RNA experiments also require control of operation time, temperature, and nuclease contamination.

A suitable strategy is to first perform pre-lysis with lysozyme, lysostaphin, or combined enzymes, followed by SDS, Proteinase K, and nucleic acid protection systems to complete lysis. For difficult-to-lyse bacteria and complex samples, mechanical disruption can be added, but excessive shearing should be avoided in long-fragment DNA experiments.

5.2 Protein Extraction

Protein extraction requires distinguishing total proteins, soluble proteins, membrane proteins, and cell wall-associated proteins. If protein activity needs to be preserved, strong SDS, high temperature, and excessive sonication should be avoided. If the target is total protein recovery, strong lysis systems and mechanical disruption can improve release efficiency.

Mild protein extraction can use enzymatic digestion combined with Triton X-100-type mild surfactants. Total protein or denaturing electrophoresis samples can use SDS systems. For cell wall-associated proteins, lysis strength should be optimized separately according to the localization of the target protein.

5.3 Protoplast and Spheroplast Preparation

Protoplast or spheroplast preparation requires partial or complete degradation of the cell wall while maintaining cell membrane integrity as much as possible. Such experiments must use isotonic protection systems to prevent cells from immediately rupturing due to osmotic pressure changes after cell wall removal.

Sucrose and sorbitol are commonly used for isotonic protection. Enzyme concentration and treatment time should be controlled, and morphological changes should be observed under a microscope. If samples rapidly rupture, it usually indicates insufficient isotonic protection or excessive enzymatic digestion.

5.4 Cell Wall Structure Analysis

If peptidoglycan composition, crosslinking degree, or cell wall modifications are being studied, overly strong lysis should be avoided to prevent loss of structural information. Such experiments are more suitable for targeted enzymatic digestion, mild extraction, and subsequent mass spectrometry, chromatography, or specific staining analysis.

Cell wall structure analysis should not directly copy nucleic acid extraction lysis workflows. Nucleic acid extraction emphasizes sufficient release, whereas cell wall analysis emphasizes preservation of structural information. The logic for method selection is different between the two.

6 Product Selection Related to Bacterial Cell Wall Degradation Technology

Product Module	Cat. No.	Product Name	Grade & Purity	Application Positioning
Peptidoglycan glycosidic bond hydrolysis	L105521	Lysozyme,from egg white	Bioactive, ActiBioPure™, Native, High Performance, EnzymoPure™, ≥20000U/mg enzyme powder	Used for routine enzymatic bacterial cell wall degradation; suitable for Gram-positive bacterial pre-lysis and nucleic acid/protein extraction pretreatment
Peptidoglycan glycosidic bond hydrolysis	L274271	Lysozyme, Egg White	EnzymoPure™, Ultra pure	Used in high-purity lysozyme lysis systems; suitable for experiments requiring low background in downstream nucleic acid or protein detection
Peptidoglycan glycosidic bond hydrolysis	L128640	Lysozyme from chicken egg white	Native, EnzymoPure™, ≥5,000 units/mg dry weight	Used for routine bacterial cell disruption, Gram-positive bacterial lysis, and preliminary optimization of lysis conditions
Peptidoglycan glycosidic bond hydrolysis	L128641	Lysozyme from chicken egg white(Purified,Salt Free)	Native, EnzymoPure™, ≥8,000 units/mg dry weight	Salt-free lysozyme, suitable for cell wall degradation experiments requiring customized buffer systems
Peptidoglycan glycosidic bond hydrolysis	rp148458	Recombinant Human Lysozyme protein	Animal Free, Carrier Free, Bioactive, ActiBioPure™, High Performance, ≥90%(SDS-PAGE)	Used for lysozyme-related functional research, antibacterial activity research, or recombinant protein controls
Peptidoglycan glycosidic bond hydrolysis	np001031	Lysozyme from Human Neutrophil	Bioactive, ActiBioPure™, Native, High Performance, EnzymoPure™, ≥95%(SDS-PAGE), >30,000 sugar U/mg protein; Pre-lyophilization Protein Concentration: See COA	Suitable for innate immunity, antibacterial mechanism research, and functional studies of neutrophil-derived lysozyme
Staphylococcal cell wall degradation	L304912	Recombinant Lysostaphin	Recombinant, EnzymoPure™, ≥90%(SDS-PAGE), ≥1200 U/mg solid	Specifically cleaves the pentaglycine bridge in staphylococcal peptidoglycan; suitable for staphylococcal lysis, DNA/RNA extraction, and protein release
Staphylococcal cell wall degradation	L755639	Recombinant Lysostaphin	Bioactive, Recombinant, ActiBioPure™, High Performance, EnzymoPure™, ≥90%(HPLC), >3000 U/mg protein	High-activity recombinant lysostaphin, suitable for cell wall disruption of difficult-to-lyse samples such as Staphylococcus aureus
Outer membrane permeabilization/metal chelation	E196386	EDTA Buffer	0.5M EDTA solution (pH8.0)	Used for Gram-negative bacterial outer membrane permeabilization and enhancing lysozyme access to the peptidoglycan layer
Outer membrane permeabilization/metal chelation	E301914	EDTA Buffered Solution	1M,pH8.0	High-concentration EDTA stock solution, suitable for preparation of lysis buffers and nucleic acid extraction systems
Outer membrane permeabilization/metal chelation	E112487	Ethylenediaminetetraacetic acid	AR, ≥99.5%	Used for preparing EDTA lysis buffers and weakening Gram-negative bacterial outer membrane stability
Outer membrane permeabilization/metal chelation	E112485	Ethylenediaminetetraacetic acid	Anhydrous Grade, Ultra pure, ≥99.5%(T)	Suitable for high-purity buffer preparation and reducing impurity interference with enzymatic digestion or downstream detection
Outer membrane permeabilization/metal chelation	E112488	Ethylenediaminetetraacetic acid（EDTA）	PrimorTrace™, ≥99.99% metals basis	Suitable for enzymatic, nucleic acid, or mass spectrometry-related sample processing sensitive to metal impurities
Outer membrane permeabilization/metal chelation	E112489	Ethylenediaminetetraacetic acid(EDTA)	for Cell culture, ≥99%	Can be used for metal ion chelation in mild cell/microbial sample treatment systems
Outer membrane permeabilization/metal chelation	D684233	Disodium ethylenediaminetetraacetate	≥99%	Commonly used to prepare EDTA-Na₂ buffers, suitable for outer membrane permeabilization and nucleic acid extraction systems
Strong lysis auxiliary reagent	S743045	10% SDS	DNase, RNase & Protease free, Sterile	Used for nucleic acid extraction and total bacterial lysis; suitable for nuclease-free lysis systems
Strong lysis auxiliary reagent	S301875	SDS Solution	10%	Used for preparing bacterial lysis buffers and assisting membrane disruption and protein denaturation
Strong lysis auxiliary reagent	S118591	Sodium dodecyl sulfate	Suitable for molecular biology, ≥98.5%(GC)	Suitable for DNA/RNA extraction and molecular biology lysis systems
Strong lysis auxiliary reagent	S108349	Sodium dodecyl sulfate	Ultra pure, ≥99%(GC)	Used for preparation of high-purity SDS lysis buffers; suitable for experiments requiring low background
Strong lysis auxiliary reagent	S108350	Sodium dodecyl sulfate(SDS)	ACS, ≥99%	Used for routine chemical lysis, total protein release, and membrane lysis after cell wall degradation
Strong lysis auxiliary reagent	S432155	Sodium dodecyl sulfate(SDS)	Reagent Grade, High-purity, ≥98.5%(GC)	Used for routine laboratory bacterial lysis buffers and protein denaturation systems
Mild membrane lysis/permeabilization auxiliary	T434386	Triton™ X-100	UltraBio™, Ultra pure	Used for mild membrane permeabilization and protein release; suitable for auxiliary lysis after enzymatic digestion
Mild membrane lysis/permeabilization auxiliary	T109027	Triton™ X-100	Suitable for molecular biology	Used for bacterial lysis buffers, membrane protein release, and mild lysis systems
Mild membrane lysis/permeabilization auxiliary	T109026	Triton™ X-100	Biochemical	Used for routine mild lysis or surfactant-assisted cell wall disruption
Washing/mild auxiliary lysis	T104863	TWEEN ® 20	viscous liquid	Used for washing, reducing nonspecific adsorption, and mild membrane permeabilization assistance
Washing/mild auxiliary lysis	T476411	TWEEN® 20	non-ionic, aqueous solution, 10% (w/v)	Ready-to-use Tween-20 aqueous solution, suitable for post-lysis washing or mild auxiliary systems
Washing/mild auxiliary lysis	T434505	TWEEN® 20	Suitable for molecular biology, viscous liquids	Used for molecular biology-related wash buffers and mild auxiliary lysis systems
Washing/mild auxiliary lysis	T434506	TWEEN® 20	for Cell culture, viscous liquid	Suitable for mild washing and low-strength surfactant treatment of cell/microbial samples
Protein digestion/nucleic acid extraction auxiliary	P274341	Proteinase K	BioReagent, EnzymoPure™	Used for protein digestion during nucleic acid extraction, assisting DNA/RNA release and reducing nuclease interference
Protein digestion/nucleic acid extraction auxiliary	P109033	Proteinase K	Bioactive, Recombinant, ActiBioPure™, High Performance, EnzymoPure™, ≥95%, lyophilized powder，≥30 units/mg protein；expressed in Pichia pastoris	High-performance recombinant Proteinase K, suitable for high-quality nucleic acid extraction and protein removal after bacterial lysis
Protein digestion/nucleic acid extraction auxiliary	P301575	Proteinase K from Tritirachium album	EnzymoPure™, ≥500 units/mL, buffered aqueous glycerol solution	Liquid Proteinase K, suitable for rapid addition to nucleic acid extraction lysis systems
Protein digestion/nucleic acid extraction auxiliary	P128666	Proteinase K from Tritirachium album limber	EnzymoPure™, ≥20 units/mg dry weight	Used for protein digestion during routine DNA/RNA extraction
Protein digestion/nucleic acid extraction auxiliary	P1520268	Proteinase K Solution (20 mg/mL)	BioReagent, DNase, RNase free, Suitable for molecular biology, Sterile, ≥95%(Native-PAGE), 20 mg/mL	Ready-to-use Proteinase K solution, suitable for bacterial nucleic acid extraction and lysis buffer preparation
Protein digestion/nucleic acid extraction auxiliary	P1520269	Proteinase K Solution (40 mg/mL)	BioReagent, DNase, RNase free, Suitable for molecular biology, Sterile, ≥95%(Native-PAGE), 40 mg/mL	High-concentration ready-to-use Proteinase K solution, suitable for high-input samples or samples with strong protein background
Cell wall/Gram staining auxiliary	C110702	Crystal violet	ACS, ≥90%	Used for Gram staining or bacterial morphology observation, assisting evaluation of cell wall structural status
Cell wall/Gram staining auxiliary	C110703	Crystal violet	AR, ≥90%	Used for routine bacterial staining and cell wall status observation
Cell wall/Gram staining auxiliary	C196471	Crystal violet	0.1% in water	Ready-to-use crystal violet aqueous solution, suitable for Gram staining and microbial morphology observation
Cell wall/Gram staining auxiliary	C1520409	Crystal Violet Aqueous Solution (5%)	BioReagent, Suitable for microbiology, Biological Stain, for Microscopy, 5%	Microbiology-grade crystal violet staining solution, suitable for bacterial staining and comparison of morphology before and after lysis
Membrane integrity/lysis evaluation	P266304	Propidium iodide（PI）	≥98%(HPLC)	Used for membrane integrity detection and evaluation of bacterial lysis, membrane damage, or death ratio
Membrane integrity/lysis evaluation	P113815	Propidium iodide (PI)	≥94%	Used for staining membrane-compromised/dead bacteria and evaluating lysis effects; live/dead ratios should be interpreted together with total bacterial dyes, live-cell dyes, or flow-cytometry gating
Membrane integrity/lysis evaluation	P422887	Propidium iodide（PI）	10mM in DMSO	PI stock solution, suitable for rapid preparation of membrane integrity detection working solution
Isotonic protectant	S112234	Sucrose	Moligand™, Suitable for molecular biology, ≥99.5%(HPLC)	Used for isotonic protection during protoplast/spheroplast preparation to prevent osmotic lysis after cell wall removal
Isotonic protectant	S112226	Sucrose	Moligand™, Ultra pure, ≥99.9%, RNase,DNase Free	Suitable for RNA/DNA-related protoplast preparation or high-cleanliness isotonic systems
Isotonic protectant	S112236	Sucrose	Moligand™, for Cell culture, Suitable for insect cell culture, ≥99.5%	Used for cell-friendly isotonic protection systems and mild cell treatment
Isotonic protectant	D755727	D-Sorbitol	UltraBio™, ≥99%(HPLC)	Used for osmotic protection during protoplast/spheroplast preparation
Isotonic protectant	S104837	D-Sorbitol	Ultra pure, ≥99.5%(HPLC)	Suitable for high-purity isotonic protection systems and reducing impurity effects on downstream analysis
Isotonic protectant	S299575	D-Sorbitol solution	1mol/L	Ready-to-use sorbitol solution, suitable for rapid preparation of protoplast isotonic protection systems

7 Common Problems and Result Interpretation

7.1 Low Nucleic Acid Yield

Low nucleic acid yield is commonly caused by insufficient cell wall lysis, low sample input, nucleic acid degradation, or mismatch between lysis buffer and bacterial species. For Gram-positive bacterial samples, enzyme digestion conditions should be checked first. For mixed microbial community samples, lysis bias should be considered.

7.2 Low Protein Recovery

Low protein recovery may be related to insufficient cell wall disruption, ineffective solubilization of membrane proteins, protein precipitation, or post-lysis degradation. If the target is soluble protein, mild lysis should be optimized first. If the target is a cell wall- or membrane-associated protein, lysis strength should be increased and the detergent system adjusted.

7.3 Severe DNA Fragmentation

Severe DNA fragmentation is often seen with excessive mechanical disruption, prolonged sonication, or excessive shear force during operation. For long-fragment DNA extraction, vigorous mixing and strong mechanical treatment should be reduced, and mild enzymatic digestion with low-shear lysis workflows should be prioritized.

7.4 Unstable Protoplasts

Unstable protoplasts are usually associated with insufficient isotonic protection, excessive enzymatic digestion, or cell membrane damage. If rapid rupture or increased cell debris is observed under the microscope, degradation strength should be reduced and the osmotic protection system should be checked.

7.5 Bias in Mixed Microbial Community Results

If sequencing results show an abnormally low proportion of thick-walled bacteria, technical bias caused by insufficient lysis may be involved. Mixed microbial community samples should avoid a single mild enzymatic digestion condition. Combined enzymes and mechanical assistance are recommended to improve lysis consistency across different bacterial types.

The core of bacterial cell wall degradation technology is to select an appropriate cell disruption combination according to cell wall structure, sample type, and downstream application. Lysozyme is suitable for basic peptidoglycan degradation, lysostaphin is suitable for staphylococci, Gram-negative bacteria usually require EDTA-assisted outer membrane permeabilization, and complex samples require attention to lysis bias.

For more related articles, please see below:

[1] Staining experiments of bacterial cell walls

[2] Structural Features of Lysozyme and Advances in Its Applications