Microbial Biodeterioration of Material and it’s Control Arish Daud Musawer Ali Sagheer Ahmed Anil Yousaf Masih Danish Gul
Biodeterioration • Bio-life • Deterioration- destruction, impairment • H. J. Hueck gave the first definition in a paper in 1965: • “any undesirable change in the properties of a material caused by the vital activities of an organism” • Text book defines it as “any undesirable change occurring in a natural or processed material of economic importance, brought about by the activities of living organisms whether plants, animals or, microorganisms”
Biodeterioration vs. Biodegradation • Biodegradation is also impairing things by living organisms, so does that mean both terms have same meaning? NO! • Biodegradation- • positive aspects of microbial activities • Biodeterioration • negative aspects of microbial activities • Depends on the location of microbial activity
Fallen tree decaying Wet Rot decaying ceiling
Biodeterioration of solid materials • Biodeterioration of solid materials starts with formation of a biofilm
Biodeterioration Cont… • Biodeteriogenesis functions like a disease • Has three phases: • Infection/Contamination • Incubation • Manifestation (Symptoms start appearing) • Economic aspects • Cost of prevention (physical-cooling or chemical-preservatives etc.) • Material replacement • Restoration
Biodeterioration of Stored Plant Food Material Anil Yousaf Masih
Non Food Animal Products Sagheer Ahmad Malik
Non Food Animal Products Hides(animal skin treated for human use) Leather Stone and related building materials Cellulosic materials
Leather • Contain fatty and proteinaceous debris • Could be degraded by proteolytic and lipolytic enzymes by micro-organisms • To avoid this biocides are used
Steps for leather production • Soaking in water Susceptible to attack by bacteria B. subtilis etc Enzyme are secreted at this stage. Active even after the death of micro-organisms • Liming, deliming and then tanning • Drying • 80% humidity favours micro-organisms growth • Fungi is primary biodeteriogens • Bacteria are usually secondary colonizers
Wool, fur and feathers • composed of cystine-rich protein keratin • Losses are because of keratinophilic fungi and certain bacteria • The damages are pigmentation, odour production and loss of tensile strength • incorporation of biocides during processing prevents from the problem
Stone and related building materials • prone to microbial attack mainly Algae, cyanobacteria, fungi or lichens. • Causes soiling, excessive expansion, widening of cracks • excretion of corrosive metabolites • Several organic acids solubilize calcium carbonate • oxalic and citric acid solubilize • silicates
Continue • Nitrifying bacteria, may also cause damage by solubilizing calcium-based rock, as their oxidation of ammonia to nitrate leads to the formation of a relatively soluble salt, calcium nitrate. • Problems can be handled by frequent painting, or cleaning with biocidal washes of bleach, phenolics.
Cellulosic materialswood, card,paper and plant fiber textiles • susceptible to fungal attack, some bacteria, notably Cellulomonas and Cellvibrio specie. • Enzymes are cellulase, a complex of several enzymes including exo-b-1,4-glucanase, endo-b-1,4-glucanase and b-glucosidase, and hemicellulases • Damage ranges from loss of quality to major reductions in strength. • They do not spread beyond the damp areas and are far easier to treat by biocides
Degradation of Metals Musawar Ali
Degradation of Metals There are three main routes of microbial corrosion of metals. Concentration of cells Release of corrosive metabolic products Removal of cathodic hydrogen by sulphate reducing bacteria
Microbial concentration cells • As a result of oxygen gradient • Microbes on borders have access to more oxygen so they become cathodic • Oxygen limited centre becomes anodic • Metal in the oxygen deficient portion loses electrons and becomes positively charged and reacts with OH- ions to form insoluble metal hydroxide.
Corrosive metabolic products • Microorganisms produce organic and inorganic acids cause metal corrosion • examples: • Sulphur oxidizers produce highly corrosive sulphuric acid which degrades fuel tanks. • Sulphate reducing bacteria produce hydrogen sulphide which can cause sulphide stress cracking. Susceptiblealloys, especially steels, react with hydrogen sulfide, forming metal sulfides and atomic hydrogen as a result of corrosion.
Plastic degradation • Plastics are polymeric materials that include polyethylenes, polystyrene, polyvinylchloride and polyesters. • Plastic material are largely resistant to microbial attack but the other materials added to the plastic are suseptible to microbial attack. • initially the microbes metabolize these additives and form a surface biofilm as a result of which plastic becomes fragile and discolored.
Biodeterioration of Cosmetics and Pharmaceuticals Arish Daud
Pharmaceutical product classification • Non-sterile: solids (tablets, capsules and powders), • liquids (suspensions and syrups), creams and lotions; • Sterile: injectables (parenterals), both single dose and multidosedrugs, intravenous infusions, etc., along with products for use in and around the eye area, including drops, lotions, ointment, washes and contact lens cleaning solutions.
Cosmetics preparation and microbial growth • Reasons for Unsaleable of products • The presence of low levels of acutely pathogenic microorganisms or higher levels of opportunistic pathogens. • Contamination with toxic microbial metabolites that can persist even when the producer microorganisms are • dead or removed.
The occurrence of detectable physical and/or chemical changes. • Loss of function of the active ingredient(s). • The presence of pathogens or potential pathogens • Application of spoilage products on healthy people and hospital patients
Presence of Microbial toxins • Relation to injectable drugs • Myotoxins and Endotoxins mainly (pyrogens) • Use of ultrapure water for injections
Chemical and physicochemical changes • Change depends upon chemical structure of ingredients and physiochemical nature of product • Initiation of attack by pathogens to cause change of nature and structure of product • Oils and fats are particularly susceptible to microbial attack
Loss of function of the active ingredient • The active ingredient is often present at relatively low Concentrations • Active ingredient may be therapeutic or antimicrobial agents, and in cosmetics and toiletries they are mostlydetergents,coloring agents • Bacterial species attack the detergent in cosmetics and toileteries are Pseudomonas, Citrobacter and Aerobacterspecies
Factors influencing microbial spoilage • Microbial growth is determined by nutrient status of the product formulation, pH, oxygen concentration, water activity, temperature and the efficacy of the oxygen concentration of the preservative system employed
Moisture content of a product • Redox potential, the oxidation–reduction balance • The pH of a product obviously influences the range of microorganisms that will grow • Package design also influences the susceptibility of a product to Biodeterioration
Assessment of microbial contamination • (microbiological quality control) • Microbial quality control is conducted to: • monitor microbial contamination of raw materials; • monitor and confirm the efficacy of operations such as sterilization; • control the danger from pathogenic microorganisms by confirming their absence
Verify the expected storage life and provide an estimate of perishability • Sensitive analytical tests are available for the detection of very low levels of mycotoxins. • Amoebocytelysateassay • Very sensitive and can detect as little as 10-12 g/ml.
Detection of microbial enzymes • is often important • Other tests that may be performed on the products are ‘challenge tests’ ( utilization of BiodeteriogensPseudomonas aeruginosa (Gram-negative), Staphylococcus • aureus (Gram-positive), Candida albicans (yeast) • and Aspergillusniger (filamentous fungus)
Preservatives • Chemicals or substances that preserves or protects the substance added to. • Aim of using preservatives: • Kill or inhibit growth of microbes • Which one to add? • The least toxic that will do the Job! • How much to add? • As little as possible BUT! Don’t • Underdose-could cause development of resistance • Overdose- less economical, and could be toxic
What’s a good preservative like? • Broad Spectrum • Free from toxicity, irritancy and allergenicity, • Stable, • Compatible with all other formulation ingredients • Free from odor and flavor. • Has no effect on chemical or physical properties of the product.
Cont… • Final Choice of Preservative for a substance depends on: • Activity spectrum • Solubility • Stability • Volatility • Toxicity • Color, • Odor, • Irritancy, • Taste, • And especially pH: • Preservatives have a small range of pH to work on.
Availability of Preservative in the Product • Not all the preservative present in the product is available for the “preservation” • The unavailable preservative could exhibit allergenecity or toxicity. • Multiple factors for this unavailability • Basic factor • Most of the Cosmetic products are multiphase systems • Are in the form of emulsions
Preservatives for Cosmetics and Pharmaceuticals Some of the Preservatives are: • Alcohols • Widely used disinfectant and antiseptic • Ineffective against endospores • 50-70% ethanol denatures proteins and solubilize lipids • Formaldehyde • Highly reactive • Reacts with NH2, SH and COOH group • Possibly carcinogenic • Formaldehyde donors, like Germall 115-imidazolidinyl urea now preferred • Less carcinogenic
Cont… • Quaternary Ammonium Cpds. • Surfactants • Skin antiseptics and disinfectants • Preservative for ophthalmic preparations, like eye drops, contact lens solutions • Activity enhanced by EDTA • Less active in presence of organic cpds. • Silver nitrate • General antiseptic • Used in pharmaceutical products for the eyes
When different preservatives are mixed up…! • Great benefits have been gained: • Increase in activity spectrum • Reduced irritancy and toxicity (low level of each is used) • Decreased chance of development of resistant microorganisms • Synergistic preservative effects • Prolongation of preservative action • Compensation for physicochemical limitations.
Biodeterioration Testing • Testing of materials for resistance to biodeterioration and also testing for the efficacy of biocidaltreatments • Two ways to do it: • Soil Burial tests • Material is buried in the soil for some time, • Later removed and checked for changes in color, tensile strength, loss of mass etc. OR • Specifically challenged with a known biodeteriogen: • Provide favorable conditions like pH, temperature, humidity etc. • After some period of incubation test the material for changes and loss in different properties.