Combination of selected enzymes with cetyltrimethylammonium bromide in biofilm inactivation, removal and regrowth

Understanding the Influence of Rheology on Biofilm Adhesion and Implication for Food Safety

Understanding biofilm rheology is crucial for industrial and domestic food safety practices. This comprehensive review addresses the knowledge gap on the rheology of biofilm. Specifically, the review explores the influence of fluid flow, shear stress, and substrate properties on the initiation, structure, and functionality of biofilms, as essential implications for food safety. The viscosity and shear-thinning characteristics of non-Newtonian fluids may impact the attachment and detachment dynamics of biofilms, influencing their stability and resilience under different flow conditions. The discussion spans multiple facets, including the role of extracellular polymeric substances (EPSs) in biofilm formation, the impact of rheological attributes of biofilm on their adhesion to surfaces, and the influence of shear forces between biofilms and substrate's surface characteristics on biofilm stability. Analytical techniques, encompassing rheometry, microscopy, and molecular biology approaches, are scrutinized for their contributions to understanding these interactions. The paper delves into the implications for the food industry, highlighting potential risks associated with biofilm formation and proposing strategies for effective control and prevention. Future research directions and the integration of rheological considerations into food safety regulations are underscored as pivotal steps in mitigating biofilm-related risks. The synthesis of microbiology, materials science, and engineering perspectives offers a multidimensional exploration of rheology-biofilm interactions, laying the groundwork for informed interventions in diverse industrial settings.

Microbial enzymes as powerful natural anti-biofilm candidates

Bacterial biofilms pose significant challenges, from healthcare-associated infections to biofouling in industrial systems, resulting in significant health impacts and financial losses globally. Classic antimicrobial methods often fail to eradicate sessile microbial communities within biofilms, requiring innovative approaches. This review explores the structure, formation, and role of biofilms, highlighting the critical importance of exopolysaccharides in biofilm stability and resistance mechanisms. We emphasize the potential of microbial enzymatic approaches, particularly focusing on glycosidases, proteases, and deoxyribonucleases, which can disrupt biofilm matrices effectively. We also delve into the importance of enzymes such as cellobiose dehydrogenase, which disrupts biofilms by degrading polysaccharides. This enzyme is mainly sourced from Aspergillus niger and Sclerotium rolfsii, with optimized production strategies enhancing its efficacy. Additionally, we explore levan hydrolase, alginate lyase, α-amylase, protease, and lysostaphin as potent antibiofilm agents, discussing their microbial origins and production optimization strategies. These enzymes offer promising avenues for combating biofilm-related challenges in healthcare, environmental, and industrial settings. Ultimately, enzymatic strategies present environmentally friendly solutions with high potential for biofilm management and infection control.

Combinatorial therapeutic enzymes to combat multidrug resistance in bacteria

AIMS

Antibiotic resistance including multidrug resistance (MDR) is a negative symbol to the human health system because it loses the capability to treat infections. Unfortunately, the available antibiotics do not show an effective therapeutic response against bacterial infections. In the situation of global antibiotic unresponsiveness, enzymatic therapy especially in combinatorial form seems an effective approach to control bacterial infection and combat resistance. The article is important because it focuses on combinatorial enzymatic therapy that has multiple properties (effective antibacterial performances, antibiofilm capacity, immunomodulators, targeted actions, synergistic actions, multiple targeting, and resistance-proof properties) and can address antibiotic resistance effectively.

MATERIALS AND METHODS

We searched the related topics with Pubmed, Scopus, and Google Scholar databases and finally 73 relevant papers were reviewed in detail and cited in this article.

KEY FINDINGS

Discusses properties of combinatorial therapeutic enzymes made it an accomplished means over antibiotic therapy. This article discusses the need for combinatorial enzymatic therapy against bacterial infection, its distinguished features, and properties with multi-mechanistic antibacterial action. It discussed the European Medicine Agency and Food and Drug Administration-approved therapeutic enzymes (antibacterial and antibiofilm).

SIGNIFICANCE

This article provided the possible combination of the enzyme that may be used as an antibacterial agent along with limitations and future scope of combinatorial antibacterial enzymatic agents. This article could draw the attention of researchers to combinatorial therapeutic enzymatic molecules as effective and futuristic therapy to overcome the problem of multiple antibiotic resistance in bacteria.

Secreted Metabolites from Pseudomonas, Staphylococcus, and Borrelia Biofilm: Modulation of Immunogenicity by a Nutraceutical Enzyme and Botanical Blend

Bacterial biofilms are hardy, adaptable colonies, evading immune recognition while triggering and sustaining inflammation. The goals for this study were to present a method for testing the immunogenicity of secreted metabolites from pathogenic biofilm and to document whether biofilm treated with a nutraceutical enzyme and botanical blend (NEBB) showed evidence of reprogrammed bacterial metabolism, potentially becoming more recognizable to the immune system. We screened immune-modulating properties of metabolites from established biofilm from Pseudomonas aeruginosa (Pa), Stapholycoccus simulans (Ss), and Borrelia burgdorferi (Bb). Secreted metabolites significantly increased the cytokine production by human peripheral blood mononuclear cells, including Interleukin-1-beta (IL-1β), Interleukin-6 (IL-6), macrophage inflammatory protein-1-alpha (MIP-1α), tumor necrosis factor-alpha (TNF-α), interleukin-1 receptor antagonist (IL-1ra), and interleukin-10 (IL-10). Pa metabolites triggered the most robust increase in IL-1β, whereas Bb metabolites triggered the most robust increase in IL-10. NEBB-disrupted biofilm produced metabolites triggering altered immune modulation compared to metabolites from untreated biofilm. Metabolites from NEBB-disrupted biofilm triggered increased MIP-1α levels and reduced IL-10 levels, suggesting a reduced ability to suppress the recruitment of phagocytes compared to untreated biofilm. The results suggest that nutraceutical biofilm disruption offers strategies for inflammation management in chronic infectious illnesses. Further clinical studies are warranted to evaluate clinical correlations in infected human hosts.

pH-responsive bentonite nanoclay carriers control the release of benzothiazolinone to restrain bacterial wilt disease

Ralstonia solanacearum (R. solanacearum) is one of the most devastating pathogens in terms of losses in agricultural production. Bentonite (Bent) is a promising synergistic agent used in development of effective and environmentally friendly pesticides against plant disease. However, the synergistic mechanism of Bent nanoclays with benzothiazolinone (BIT) against R. solanacearum is unknown. In this work, acid-functionalized porous Bent and cetyltrimethylammonium bromide (CTAB) were employed as the core nanoclays, and BIT was loaded into the clay to form BIT-loaded CT-Bent (BIT@CT-Bent) for the control of bacterial wilt disease. BIT@CT-Bent exhibited pH-responsive release behavior that fit the Fickian diffusion model, rapidly releasing BIT in an acidic environment (pH = 5.5). The antibacterial effect of BIT@CT-Bent was approximately 4 times greater than that of the commercial product BIT, and its biotoxicity was much lower than that of BIT under the same conditions. Interestingly, R. solanacearum attracted BIT@CT-Bent into the nanocomposites and induced cytoplasmic leakage and changes in membrane permeability, indicating an efficient and synergistic bactericidal effect that rapidly reduced bacterial density. In addition, BIT@CT-Bent significantly inhibited R. solanacearum biofilm formation and swimming activity, by suppressing the expression of phcA, solR and vsrC. Indeed, exogenous application of BIT@CT-Bent significantly suppressed the virulence of R. solanacearum on tobacco plants, with control effect of 75.48%, 72.08% and 66.08% at 9, 11 and 13 days after inoculation, respectively. This study highlights the potential of using BIT@CT-Bent as an effective, eco-friendly bactericide to control bacterial wilt diseases and for the development of sustainable crop protection strategies.

Marine antifouling properties of enzyme modified polyaniline coated stainless steel surface

On solid surfaces immersed in a liquid medium, a biofilm layer which is called biofouling formed over time by organic molecules and microorganisms. It is important to produce new eco-friendly ideas can prevent this undesired phenome. In this study, we focused on the antifouling performance of polyaniline (PANI), whose anticorrosive properties have been already known. The main purpose of this study was to immobilize hydrolytic enzymes that could break down biomolecules and microorganisms and how this would contribute to the antifouling performance of the PANI coating. When α-amylase, DNAse, glucose oxidase, α-chymotrypsin, lipase and pectinase enzymes immobilized into PANI that was synthesized in ammonium oxalate (PANIAO) and sodium salicylate (PANISS) electrolytes, α-amylase containing film (PANISS-A) showed the highest performance (76.5% antifouling activity). The surface properties after keeping in the Mediterranean Sea for 12 days were compared by digital photography, Scanning Electron microscope (SEM) and fluorescence microscope images, also with Energy Dispersive X-Ray (EDX) analysis and crystal violet staining. Carbohydrate and protein amounts and CFU (Colony Forming Units) values of biofilms formed on the surface for bare, PANISS and PANISS-A coupons after keeping 12 days in the Mediterranean Sea were determined. Vibrio species (V.harveyi, V.alginolyticus, V.parahaemolyticus) were detected in the biofilms by Matrix- Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry (MALDI-TOF MS) analysis.

Extracellular matrix-degrading enzymes as a biofilm control strategy for food-related microorganisms

Biofilm is one of the major problems in food industries and is difficult to be removed or prevented by conventional sanitizers. In this review, we discussed the extracellular matrix-degrading enzymes as a strategy to control biofilms of foodborne pathogenic and food-contaminating bacteria. The biofilms can be degraded by using the enzymes targeting proteins, polysaccharides, extracellular DNA, or lipids which mainly constitute the extracellular polymeric substances of biofilms. However, the efficacy of enzymes varies by the growth medium, bacterial species, strains, or counterpart microorganisms due to a high variation in the composition of extracellular polymeric substances. Several studies demonstrated that the combined treatment using conventional sanitizers or multiple enzymes can synergistically enhance the biofilm removal efficacies. In this review, the application of the immobilized enzymes on solid substrates is also discussed as a potential strategy to prevent biofilm formation on food contact surfaces.

Comparison of the efficacy of physical and chemical strategies for the inactivation of biofilm cells of foodborne pathogens

Biofilm formation is a strategy in which microorganisms generate a matrix of extracellular polymeric substances to increase survival under harsh conditions. The efficacy of sanitization processes is lowered when biofilms form, in particular on industrial devices. While various traditional and emerging technologies have been explored for the eradication of biofilms, cell resistance under a range of environmental conditions renders evaluation of the efficacy of control challenging. This review aimed to: (1) classify biofilm control measures into chemical, physical, and combination methods, (2) discuss mechanisms underlying inactivation by each method, and (3) summarize the reduction of biofilm cells after each treatment. The review is expected to be useful for future experimental studies and help to guide the establishment of biofilm control strategies in the food industry.

Natural Antimicrobials for Listeria monocytogenes in Ready-to-Eat Meats: Current Challenges and Future Prospects

Listeria monocytogenes, an intra-cellular, Gram-positive, pathogenic bacterium, is one of the leading agents of foodborne illnesses. The morbidity of human listeriosis is low, but it has a high mortality rate of approximately 20% to 30%. L. monocytogenes is a psychotropic organism, making it a significant threat to ready-to-eat (RTE) meat product food safety. Listeria contamination is associated with the food processing environment or post-cooking cross-contamination events. The potential use of antimicrobials in packaging can reduce foodborne disease risk and spoilage. Novel antimicrobials can be advantageous for limiting Listeria and improving the shelf life of RTE meat. This review will discuss the Listeria occurrence in RTE meat products and potential natural antimicrobial additives for controlling Listeria.

Biofilm control strategies in the light of biofilm-forming microorganisms

Biofilm is a complex consortium of microorganisms attached to biotic or abiotic surfaces and live in self-produced or acquired extracellular polymeric substances (EPSs). EPSs are mainly formed by lipids, polysaccharides, proteins, and extracellular DNAs. The adherence to the surface of microbial communities is seen in food, medical, dental, industrial, and environmental fields. Biofilm development in food processing areas challenges food hygiene, and human health. In addition, bacterial attachment and biofilm formation on medical implants inside human tissue can cause multiple critical chronic infections. More than 30 years of international research on the mechanisms of biofilm formation have been underway to address concerns about bacterial biofilm infections. Antibiofilm strategies contain cold atmospheric plasma, nanotechnological, phage-based, antimicrobial peptides, and quorum sensing inhibition. In the last years, the studies on environmentally-friendly techniques such as essential oils and bacteriophages have been intensified to reduce microbial growth. However, the mechanisms of the biofilm matrix formation are still unclear. This review aims to discuss the latest antibiofilm therapeutic strategies against biofilm-forming bacteria.

Plasma-activated liquids for mitigating biofilms on food and food contact surfaces

Plasma-activated liquids (PALs) are emerging and promising alternatives to traditional decontamination technologies and have evolved as a new technology for applications in food, agriculture, and medicine. Contamination caused by foodborne pathogens and their biofilms has posed challenges and concerns to the food industry in terms of safety and quality. The nature of the food and the food processing environment are major factors that contribute to the growth of various microorganisms, followed by the biofilm characteristics that ensure their survival in severe environmental conditions and against traditional chemical disinfectants. PALs show an efficient impact against microorganisms and their biofilms, with various reactive species (short- and long-lived ones), physiochemical properties, and plasma processing factors playing a crucial role in mitigating biofilms. Moreover, there is potential to improve and optimize disinfection strategies using a combination of PALs with other technologies for the inactivation of biofilms. The overarching aim of this study is to build a better understanding of the parameters that govern the liquid chemistry generated in a liquid exposed to plasma and how these translate into biological effects on biofilms. This review provides a current understanding of PALs-mediated mechanisms of action on biofilms; however, the precise inactivation mechanism is still not clear and is an important part of the research. Implementation of PALs in the food industry could help overcome the disinfection hurdles and can enhance biofilm inactivation efficacy. Future perspectives in this field to expand existing state of the art to seek breakthroughs for scale-up and implementation of PALs technology in the food industry are also discussed.

Pernicious Attitude of Microbial Biofilms in Agri-Farm Industries: Acquisitions and Challenges of Existing Antibiofilm Approaches

Biofilm is a complex matrix made up of extracellular polysaccharides, DNA, and proteins that protect bacteria against physical, chemical, and biological stresses and allow them to survive in harsh environments. Safe and healthy foods are mandatory for saving lives. However, foods can be contaminated by pathogenic microorganisms at any stage from farm to fork. The contaminated foods allow pathogenic microorganisms to form biofilms and convert the foods into stigmatized poison for consumers. Biofilm formation by pathogenic microorganisms in agri-farm industries is still poorly understood and intricate to control. In biofilms, pathogenic bacteria are dwelling in a complex manner and share their genetic and physicochemical properties making them resistant to common antimicrobial agents. Therefore, finding the appropriate antibiofilm approaches is necessary to inhibit and eradicate the mature biofilms from foods and food processing surfaces. Advanced studies have already established several emerging antibiofilm approaches including plant- and microbe-derived biological agents, and they proved their efficacy against a broad-spectrum of foodborne pathogens. This review investigates the pathogenic biofilm-associated problems in agri-farm industries, potential remedies, and finding the solution to overcome the current challenges of antibiofilm approaches.

Microbially-derived cocktail of carbohydrases as an anti-biofouling agents: a 'green approach'

Enzymes, also known as biocatalysts, display vital properties like high substrate specificity, an eco-friendly nature, low energy inputs, and cost-effectiveness. Among their numerous known applications, enzymes that can target biofilms or their components are increasingly being investigated for their anti-biofouling action, particularly in healthcare, food manufacturing units and environmental applications. Enzymes can target biofilms at different levels like during the attachment of microorganisms, formation of exopolymeric substances (EPS), and their disruption thereafter. In this regard, a consortium of carbohydrases that can target heterogeneous polysaccharides present in the EPS matrix may provide an effective alternative to conventional chemical anti-biofouling methods. Further, for complete annihilation of biofilms, enzymes can be used alone or in conjunction with other antimicrobial agents. Enzymes hold the promise to replace the conventional methods with greener, more economical, and more efficient alternatives. The present article explores the potential and future perspectives of using carbohydrases as effective anti-biofilm agents.

Combined Anti-Biofilm Enzymes Strengthen the EradicateEffect of Vibrio parahaemolyticus Biofilm: Mechanism on cpsA-J Expression and Application on Different Carriers

Vibrio parahaemolyticus is a human foodborne pathogen, and it can form a mature biofilm on food and food contact surfaces to enhance their resistance to antibacterial agents. In this study, the effect of anti-biofilm enzymes (combined lipase, cellulase and proteinase K) on the inhibition and eradication of pathogen biofilm was evaluated. The biofilm content of V. parahaemolyticus showed the highest level at the incubation time of 24 h, and the combined enzymes significantly inhibited the biofilm’s development. The biofilm’s inhibition and eradication rate at an incubation time of 24 h was 89.7% and 66.9%, respectively. The confocal laser scanning microscopic images confirmed that the microcolonies’ aggregation and the adhesion of biofilm were inhibited with the combined enzyme treatment. Furthermore, combined enzymes also decreased the concentration of exopolysaccharide (EPS) and disrupted the EPS matrix network, wherein the expression of the EPS-related gene, cpsA-J, was likewise suppressed. The combined enzymes showed an excellent inhibition effect of V. parahaemolyticus biofilm on different carriers, with the highest inhibition rate of 59.35% on nonrust steel plate. This study demonstrates that the combined enzyme of lipase, cellulase and proteinase K could be a novel candidate to overcome biofilm’s problem of foodborne pathogens in the food industry.

New approach for the removal of mature biofilms formed by wild strains of Listeria monocytogenes isolated from food contact surfaces in an Iberian pig processing plant

One of the main objectives of the food industry is to guarantee food safety by providing innocuous food products. Therefore, this sector must consider all the possible biotic or abiotic contamination routes from the entry of raw materials to the release of the final product. Currently, one important problem in this regard is the presence of biofilms on food contact surfaces which can transmit pathogens such as L. monocytogenes. In industrial conditions biofilms are found in a mature state, so it is essential that when carrying out removal effectiveness studies in vitro the tests are realized with models that produce these structures in a similarly mature state. The main objective of this study was to evaluate the effectiveness of an alternative treatment (i.e. enzymatic detergent that include natural antimicrobial agents) and a conventional treatment (i.e. chlorinated alkaline) for the elimination of mature L. monocytogenes biofilms. The results showed a cell detachment from the formed mature biofilms with an effectivity of between 74.75%-97.73% and 53.94%-94.02% for the enzymatic treatment and the chlorinated alkaline detergent, respectively. On a qualitative level, it was observed that the dispersion in the structure was much higher for the enzymatic treatment than for the chlorinated alkaline, which continued to show obvious structure integrity. All this leads to the conclusion that treatments with an enzymatic detergent have a significantly greater impact on the removal of mature L. monocytogenes biofilms, although a further disinfection process would be needed, enhancing even more the treatment effectivity. This may imply that the industrial approach to addressing this problem should be modified to include new perspectives that are more effective than traditional ones.

Listeria Monocytogenes Biofilm Removal Using Different Commercial Cleaning Agents

Effective cleaning and disinfection (C&D) is pivotal for the control of Listeria monocytogenes in food processing environments. Bacteria in biofilms are protected from biocidal action, and effective strategies for the prevention and removal of biofilms are needed. In this study, different C&D biofilm control strategies on pre-formed L. monocytogenes biofilms on a conveyor belt material were evaluated and compared to the effect of a conventional chlorinated, alkaline cleaner (agent A). Bacterial reductions up to 1.8 log were obtained in biofilms exposed to daily C&D cycles with normal user concentrations of alkaline, acidic, or enzymatic cleaning agents, followed by disinfection using peracetic acid. No significant differences in bactericidal effects between the treatments were observed. Seven-day-old biofilms were more tolerant to C&D than four-day-old biofilms. Attempts to optimize biofilm eradication protocols for four alkaline, two acidic, and one enzymatic cleaning agent, in accordance with the manufacturers' recommendations, were evaluated. Increased concentrations, the number of subsequent treatments, the exposure times, and the temperatures of the C&D agents provided between 4.0 and >5.5 log reductions in colony forming units (CFU) for seven-day-old L. monocytogenes biofilms. Enhanced protocols of conventional and enzymatic C&D protocols have the potential for improved biofilm control, although further optimizations and evaluations are needed.

Quorum sensing in food spoilage and natural-based strategies for its inhibition

Food can harbor a variety of microorganisms including spoilage and pathogenic bacteria. Many bacterial processes, including production of degrading enzymes, virulence factors, and biofilm formation are known to depend on cell density through a process called quorum sensing (QS), in which cells communicate by synthesizing, detecting and reacting to small diffusible signaling molecules - autoinducers (AI). The disruption of QS could decisively contribute to control the expression of many harmful bacterial phenotypes. Several quorum sensing inhibitors (QSI) have been extensively studied, being many of them of natural origin. This review provides an analysis on the role of QS in food spoilage and biofilm formation within the food industry. QSI from natural sources are also reviewed towards their putative future applications to prolong shelf life of food products and decrease foodborne pathogenicity.

Biofilms in Food Processing Environments: Challenges and Opportunities

This review examines the impact of microbial communities colonizing food processing environments in the form of biofilms on food safety and food quality. The focus is both on biofilms formed by pathogenic and spoilage microorganisms and on those formed by harmless or beneficial microbes, which are of particular relevance in the processing of fermented foods. Information is presented on intraspecies variability in biofilm formation, interspecies relationships of cooperativism or competition within biofilms, the factors influencing biofilm ecology and architecture, and how these factors may influence removal. The effect on the biofilm formation ability of particular food components and different environmental conditions that commonly prevail during food processing is discussed. Available tools for the in situ monitoring and characterization of wild microbial biofilms in food processing facilities are explored. Finally, research on novel agents or strategies for the control of biofilm formation or removal is summarized.

Thermostable xylanase inhibits and disassembles Pseudomonas aeruginosa biofilms

Pseudomonas aeruginosa biofilms are problematic and play a critical role in the persistence of chronic infections because of their ability to tolerate antimicrobial agents. In this study, various cell-wall degrading enzymes were investigated for their ability to inhibit biofilm formation of two P. aeruginosa strains, PAO1 and PA14. Xylanase markedly inhibited and detached P. aeruginosa biofilms without affecting planktonic growth. Xylanase treatment broke down extracellular polymeric substances and decreased the viscosity of P. aeruginosa strains. However, xylanase treatment did not change the production of pyochelin, pyocyanin, pyoverdine, the Pseudomonas quinolone signal, or rhamnolipid. In addition, the anti-biofilm activity of xylanase was thermally stable for > 100 days at 45°C. Also, xylanase showed anti-biofilm activity against one methicillin-resistance Staphylococcus aureus and two Escherichia coli strains.