84.Bacterial examination of water and standard water analysis

Microbiological examination of water

Microbiological examination offers the most sensitive test for the detection of recent and potentially dangerous faecal pollution, thereby providing a hygienic assessment of water quality with high sensitivity and specificity. For this reason it is important to examine a drinking water source frequently by a simple test rather than infrequently by a more complicated test or series of tests. It is ideal to look for individual specific pathogen but it is not practical since they are few in numberthan the nonpathogenic organisms and methods to detect them are costly in time and money. Therefore indicators of human/animal pollution e.g. coliforms are used. Faecal streptococci are regularly present in the faeces in varying numbers but their number is fewer than Esch. coli and they probably die and disappear at the same rate. The presence of faecal streptococci alongwith coliforms in absence of Esch. coli is also confirmatory of faecal pollution.

Methods of analysis

Two methods have been developed for the detection of indicator bacteria in water: multiple tube method and membrane filter method.

Multiple-tube method. In the multiple-tube method different amounts of water to be tested are added to tubes containing a suitable culture medium. The bacteria present in the water reproduce and produce acid with or without gas. From the number of tubes inoculated and the number with a positive reaction, the most probable number (MPN) of bacteria present in the original water sample can be determined statistically.

The multiple-tube method is applicable to all kinds of water : it can be used with clear, coloured, or turbid water containing sewage or sewage sludge, or mud and soil particles, provided that the bacteria are homogeneously distributed in the prepared test samples.

Method

Set up following volumes of different strengths of MacConkey broth in tubes/bottles each having an inverted Durham tube to detect the presence of gas and add specified volume of water as mentioned:

One 50 ml of water to 50 ml of double strength medium.

5, 10 ml quantities each to 10 ml double strength medium.

5, 1 ml quantities each to 5 ml single strength medium.

Incubate the tubes/bottles at 37oC for 18-24 hours.

Observe change in colour and appearance of gas in Durham tubes in bottles.

The media receiving one or more of the indicator bacteria show growth and a color change which is absent in those receiving an inoculum of water without indicator bacteria. Presence of both acid and gas indicates positive reaction whereas absence of either or both these features denotes a negative reaction.

The presumptive positives are read and remaining negative bottles are reincubated for another 24 hours. Any further positives are added to the previous figures. The probable number of coliforms are read from the probability tables ofMcCrady (Table 1).

From the number and Algae is a group of autotrophic organisms, i.e. they can produce organic compounds with the aid of simple inorganic sources through a mechanism, known as photosynthesis. Photosynthesis is carried out by the organelle chloroplast, the same organelle also used by plants to accomplish the same function. They are eukaryotic, as they contain a membrane bound nucleus. They constitute a distinct group, which include simple single-celled to multicellular organisms.

Utilizing Algae

Algae is a rich source of carbohydrates, protein, enzymes and fiber. Besides, many vitamins and minerals like vitamin A, C, B1, B2, B6, niacin, iodine, potassium, iron, magnesium and calcium are abundantly found in algae. Being such a rich source of essential nutrients, they are a major source of food, especially in Asian countries like China, Japan and Korea. Nowadays, they are consumed throughout the world for their nutritional value. It is also used in producing nutritional supplements. Seaweeds are an important food supplement for animals and can also be used as fertilizers. It also has the potential of producing vegetable oil. Diatoms, the microscopic algae, are used in forensic medicine.

Agar, carrageenans and alginates are some of the important extract of algae used in food, cosmetics and pharmaceutical industries. Agar is mainly used as a preservative in canned meat and fish and as a gelling agent in food. Carrageenans are used in toothpastes, ice-creams, pet foods, lotions and as a stabilizing agent in dairy products.

In recent times, it has found applications in controlling pollution. It act as biofilter, and so is being used in the treatment of waste water to make it suitable for human use. Even some power plants also use algae to reduce the carbon dioxide emissions, where carbon dioxide is poured into some tanks or ponds in which algae are fed. In farmlands, they are used for capturing the run-off fertilizers that can pollute the water bodies.

It can be used is to produce biodiesel, which has a bright possibility to become an efficient alternative source of fuel. Its carbohydrate content is used to yield bioethanol and biobutanol. The energy density of biobutanol is similar to gasoline and it can be used in a gasoline engine without any modification. Its energy density is greater than both ethanol and methanol. In the face of the increasing prices of petroleum products, biodiesel can serve as a cheaper source of energy. Besides, it is environmental friendly and can prove to be effective in regulating global warming and climate change by controlling the level of pollution.

In addition to all these uses, it has been a part of traditional medicine in treating a number of ailments since ancient times, especially in Asian countries. Such diseases include cough, hypertension, diarrhea, gout, etc. As they have a high content of iodine, their consumption can lower the risk of goiter. Now, algae are being studied to find out if they could be used in the treatment of cancer.

It can convert the atmospheric nitrogen into ammonia, which can be used by the plants. It also produce natural pigment, which can be used as dyes. These natural pigments can emerge as a substitute for chemical dyes. Brown algae is a source of alginic acid, which is used as a thickening, stabilizing and emulsifying agent in ice-creams, dairy products, rubber, paint, shaving creams, adhesives and in the textile industry.

So, it has found a wide range of applications in recent times, as a source of essential nutrients to the treatment of a number of diseases. They play a significant role in many fields like the food, pharmaceutical, cosmetics, fuel, and textile industry. Algae are not only an important part of our ecosystem, but can also be of immense help in controlling the growing problem of pollution.distribution of positive and negative reactions, count of the most probable number (MPN) of indicator organisms in the sample may be estimated by reference to statistical tables. The test gives presumptive coliformcount as the reaction observed may occasionally be due to the presence of some organisms other than coliforms.

85 The microorganisms used in industry The use of microorganism in large scale production of food and industrial products is being done worldwide.The sources of food production in such cases may be animals or plants but the processing is done by enzymatic activities by microorganism only. Microorganism contains various enzymes which are capable of degradation of substrates. This is also known as fermentation process in which the degradations is not completed and results in useful by products. These by products include, beverages, antibiotics, milk by products etc which are used by humans as nutritive foods. With the development of technology like genetic engineering, many mutants are developed which are capable of performing extra with respect to production quality and quantity as compared to their wild types. Today pharmaceutical agents like antibiotics and other drugs are manufactured at large scale which utilizes microorganism. The history of microbiology has given us very broad spectrum antibiotics like Penicillin and Streptomycin which are still in use at large throughout the globe. Foods which are originated from animals are enzymatic ally processed by specific microorganisms resulting in increase in their nutritive value. These foods are fermented foods like Yogurt, milk by products like cheese, sweet chocolates and silage. Many algae are today used as source of protein. Fungus like mushroom is today being used as source of nutrition as well as medicine. Bacteria like Lactic acid bacteria are used in production of pure curd and other milk products. Bacteria like Bifidobacteria are being used in food industry as probiotics which helps in curing of diseases of digestive systems and intestinal disorders. Polysaccharides, polyamides, polyesters and many other varieties of biopolymers are produced by many microorganisms. These are ranging from plastics to viscous solutions. Today many researches in drug delivery and tissue engineering are being successfully done with the help of genetically manipulated microorganisms which are producing biopolymers which are having medical applications. Many wild as well as genetically mutated strains are used in industries for biosynthesis of cellulose, levan, hyaluronic acids, polysaccharides and organic acids, etc. Today many pollutants are degraded with the help of saprophytes (specific type of bacteria/fungi capable of surviving in waste organic material their by metabolism) this process is also known as biodegradation. Today bioremediation and other methods like biotransformation are used for cleaning of the environments. Today even heavy metals like mercury which is toxic and results in biomagnifications. The degradation of this is very costly by chemical and other standards technologies. Therefore the alternative method is bioremediation. Today in modern societies, lot of waste is being generated from domestic wastes. These are accumulating every day and are very harmful to not only the society but also the environment (Our mother earth). The processing of such waste using living organisms is known as biotreatment. These methods are helping society and saving earth from accumulation of hazardous wastes. This method of using microorganisms in degradation of hazardous waste is not only useful but also simple, cost effective and eco friendly. The systematic method of biotreatment is done with the help of bioreactors having aeration system, baffles which suitable for microbial enzymatic reaction. Apart from waste treatments, microorganisms are used in production of biological like insulin, serum antibodies, and essential hormones. Today with the development of technology and science, new ways of diagnosis of diseases are being used for early detection using microorganism’s e.g. rapid microbial test, enzyme employed detection, etc. One of the microbe known as Clostridium is useful in treatment of malignant cells like cancers. These organisms have the ability to selectively target cancerous cells. Streptomyces genus is used worldwide in the production of medicines and agriculture. These microorganisms process many secondary metabolites like antibiotics and plant growth hormones like Gibberilla (Microorganism used is Gibberella fujikuroi).