Solid substrate fermentation
Definition- Solid substrate fermentation used for cultivation of micro-organisms on solid substrate containing no or limited amount of water.
Used in oriental fermentations, fungal enzyme production by surface culture, mushroom production
Substrate used-
Wheat bran
cereal grains
legume seeds
wood and straw.
Types of Microorganisms grow –
Microorganisms, which grow well in solid substrate fermentation, are usually those which can tolerate a low water activity (Aw).
Micro-organisms respond differently to water activity. By reducing water activity (aw) 0.95 bacterial growth is inhibited. Fungi and yeast can grow at a water activity of 0.70 Solid substrate fermentation take different forms depending upon micro-organisms used are indigenous or pure isolated culture.
Examples:
• Composting for mushroom production involves successive activities of range of indigenous micro-organisms from mesophilic bacteria, yeasts and moulds through to thermophilic fungi and actinomycetes.
• The traditional koji process for fermentation of grains and soya beans and similar processes for production of mould industrial enzymes both using culture of Aspergillus oryzae and related species involving pure culture
Conditions suitable for Solid substrate fermentation:
• Micro-organisms industrial Solid substrate fermentation are aerobic, fermentation conditions must be designed to promote efficient transfer of oxygen and CO2 removal from substrate medium.
• Because of high concentrations of substrate per unit volume heat generation during fermentation is usually much higher p per unit volume than in liquid fermentations and low moisture content makes heat removal difficult.
• Choice of substrate particle size is of critical importance in order to minimize inter particle void spaces to facilitate gas and heat transfer. Heat removal can be facilitated by increasing aeration rate of system.
Advantages:
• Superior productivity
• Simpler technique
• Low capital investment
• Reduced energy requirement
• Low waste water output
• Lack of foam problems
Limitations:
• Heat build up
• Bacterial contamination
• Problem of scale up
• Difficulty of controlling substrate moisture level
Examples of design:
Slow continuous agitation system such as-
• rotating drums,
• tray systems and
• air flow systems
where conditioned air is blown through substrate bed in a cultivation chamber.
Rotating drums are usually equipped with an inlet and outlet for circulation of humidified air and often contain baffles or sections to agitate the contents.
Tray fermenters holding 1-2 inch deep layers of substrate are stacked in chambers usually force aerated with humidified air.
In force air cultivation chamber, bed temperature is monitored and the appropriate temperature adjustment is made to the recycling air flow.
Sunday, November 15, 2009
biotecnology in context of developing world
Biotechnology in context of developing world
Successful agriculture holds the answer to the poverty gap between rich & poor countries. In the developed world, agricultural sciences are well developed, producing an abundance of high quality products. Agricultural biotech will further improve quality, variety & yield. Will these new plant species improved by genetic engineering, find their way to developing countries, ensuring higher productivity, greater resistance to disease & be more marketable?
It is not yet clear what will happen other than that the affluent nations will become increasingly well endowed with an abundance of food. Worldwide there will be enough food for all but will it always continue to be disproportionately distributed? Biotech developments need high inputs of finance & skilled workforces- both of which are in short supply in most developing nations.
While many developing nations have successfully collaborated in the past with western biotech companies, it is salutary to note that between 1986 & 1991 the % of arrangements implemented by US biotech companies with developing countries dropped from 20% to 3% !
The ability of developing nations to avail themselves of many promise of new biotechnology will largely depend on their capacity to integrate modern developments of biotech within their own research & innovation systems, in accordance with their own needs & priorities.
Nowadays, some of the most important areas of biotech are considered with a view to achieve a broad overall understanding of existing achievements & future aims of this area of technology. However, it must be appreciated that biotech developments not will also be subject to considerable politics, economics and above all public acceptance. Finally, it has been said that most scientific disciplines pass through golden ages when new approaches open the door to rapid & fundamental expansion. Biotech is just now entering this golden period. A spectacular future lies ahead.
Successful agriculture holds the answer to the poverty gap between rich & poor countries. In the developed world, agricultural sciences are well developed, producing an abundance of high quality products. Agricultural biotech will further improve quality, variety & yield. Will these new plant species improved by genetic engineering, find their way to developing countries, ensuring higher productivity, greater resistance to disease & be more marketable?
It is not yet clear what will happen other than that the affluent nations will become increasingly well endowed with an abundance of food. Worldwide there will be enough food for all but will it always continue to be disproportionately distributed? Biotech developments need high inputs of finance & skilled workforces- both of which are in short supply in most developing nations.
While many developing nations have successfully collaborated in the past with western biotech companies, it is salutary to note that between 1986 & 1991 the % of arrangements implemented by US biotech companies with developing countries dropped from 20% to 3% !
The ability of developing nations to avail themselves of many promise of new biotechnology will largely depend on their capacity to integrate modern developments of biotech within their own research & innovation systems, in accordance with their own needs & priorities.
Nowadays, some of the most important areas of biotech are considered with a view to achieve a broad overall understanding of existing achievements & future aims of this area of technology. However, it must be appreciated that biotech developments not will also be subject to considerable politics, economics and above all public acceptance. Finally, it has been said that most scientific disciplines pass through golden ages when new approaches open the door to rapid & fundamental expansion. Biotech is just now entering this golden period. A spectacular future lies ahead.
asetic techniques
Aseptic techniques
Definition-
Aseptic technique is defined as the series of steps used to prevent contamination during manipulation of cultures and sterile culture media.
In other words, aseptic technique are procedure that allow to handle culture and sterile culture media without introducing microbial contaminants from air, water, hands, mouth or other known sources.
Knowledge of aseptic tech is essential to obtain pure culture of microbes. Air borne contaminants are the most common in microbiology because air contains minute dust particles that will have a community of microbes over them.
Aseptic tech involves following steps:
Avoid any contact between sample and pure culture, sterile medium and sterile surfaces of growth vessel with contaminating microorganism.
Cleaning of surface area with disinfectant to reduce number of potential contaminants.
Sterilization of transfer instruments.
For example- Transfer loop is sterilized by heating red hot in a Bunsen
Burner flame before and after transforming a culture.
The transfer work is to be accomplished quickly and efficiently to minimize time of exposure of material or sample to non-sterile environment such as normal air during which contamination of the culture or lab worker can occur.
Definition-
Aseptic technique is defined as the series of steps used to prevent contamination during manipulation of cultures and sterile culture media.
In other words, aseptic technique are procedure that allow to handle culture and sterile culture media without introducing microbial contaminants from air, water, hands, mouth or other known sources.
Knowledge of aseptic tech is essential to obtain pure culture of microbes. Air borne contaminants are the most common in microbiology because air contains minute dust particles that will have a community of microbes over them.
Aseptic tech involves following steps:
Avoid any contact between sample and pure culture, sterile medium and sterile surfaces of growth vessel with contaminating microorganism.
Cleaning of surface area with disinfectant to reduce number of potential contaminants.
Sterilization of transfer instruments.
For example- Transfer loop is sterilized by heating red hot in a Bunsen
Burner flame before and after transforming a culture.
The transfer work is to be accomplished quickly and efficiently to minimize time of exposure of material or sample to non-sterile environment such as normal air during which contamination of the culture or lab worker can occur.
night fungal flora
Night fungal flora
In our everyday life, we are perhaps least aware of the presence of microorganism unless we happen to suffer from an allergy of spores of molds or actinomycetes. They form an important vehicle for spread of many microorganism and the contamination of food.
Some of the important molds produce large no. of small unwettable spores which are resistant to desiccation and light damage. They become air borne as fine dry powder or dust particle by physical disturbance and wind. Spores of Penicillium and Aspergilus seem to get everywhere and are responsible for food spoilage.
Fungi like Fusarium produce easily wettable spores which are dispersed into the atmosphere in tiny droplets of water and may get distributed in field crops during wet weather.
As relative humidity of atmosphere decreases with change from night to day, the sporophores of fungi such as Cladosporium react by twisting and collapsing, throwing the spores into the atmosphere. At the some times of year, especially during middle of the day spore of Cladosporium may be the most common spores in air spora.
Many fungi have evolved mechanism for actively firing their spores into atmosphere, a process requiring high relatively humidity. Thus, spores of yeast, which are a part of microbial flora of leaf surface of plants, are present in highest no. in middle of night when relative humidity is at highest. The friuting bodies in mushrooms have produced structure that provides its own microclimate of high relative humidity so that these fungi can fire their spores into air even in middle of day.
Optimum rate of relative humidity for survival of most microorganism is between 40- 80 % low and high relative humidity cause the death of most micro organism
In our everyday life, we are perhaps least aware of the presence of microorganism unless we happen to suffer from an allergy of spores of molds or actinomycetes. They form an important vehicle for spread of many microorganism and the contamination of food.
Some of the important molds produce large no. of small unwettable spores which are resistant to desiccation and light damage. They become air borne as fine dry powder or dust particle by physical disturbance and wind. Spores of Penicillium and Aspergilus seem to get everywhere and are responsible for food spoilage.
Fungi like Fusarium produce easily wettable spores which are dispersed into the atmosphere in tiny droplets of water and may get distributed in field crops during wet weather.
As relative humidity of atmosphere decreases with change from night to day, the sporophores of fungi such as Cladosporium react by twisting and collapsing, throwing the spores into the atmosphere. At the some times of year, especially during middle of the day spore of Cladosporium may be the most common spores in air spora.
Many fungi have evolved mechanism for actively firing their spores into atmosphere, a process requiring high relatively humidity. Thus, spores of yeast, which are a part of microbial flora of leaf surface of plants, are present in highest no. in middle of night when relative humidity is at highest. The friuting bodies in mushrooms have produced structure that provides its own microclimate of high relative humidity so that these fungi can fire their spores into air even in middle of day.
Optimum rate of relative humidity for survival of most microorganism is between 40- 80 % low and high relative humidity cause the death of most micro organism
Monday, November 2, 2009
food for cancer prevention
Diet & Cancer Research
Cancer Facts - Foods for Cancer Prevention
Of the many diseases that affect people these days, cancer is among the most feared. But despite a wealth of scientific data, most people remain unaware of how they can reduce their risk of developing cancer. According to the National Cancer Institute, as much as 80 percent of all cancers are due to identified factors, and thus are potentially preventable. Thirty percent are due to tobacco use, and as much as 35 percent to 50 percent are due to foods. It is easy to control these and other risk factors.
What Is Cancer?
Cancer begins as a single abnormal cell that begins to multiply out of control. Groups of such cells form tumors and invade healthy tissue, often spreading to other parts of the body.
Carcinogens are substances that promote the development of cancerous cells.
They may come from foods, from the air, or even from within the body. Most carcinogens are neutralized before damage can occur, but sometimes they attack the cell's genetic material (DNA) and alter it. It takes years for a noticeable tumor to develop. During this time, compounds known as inhibitors can keep the cells from growing. Some vitamins in plant foods are known to be inhibitors. Dietary fat, on the other hand, is known to be a promoter that helps the abnormal cells grow quickly.
Fiber Fights Cancer
In 1970, British physician Dennis Burkitt observed that a high-fiber diet reduces diseases of the digestive tract. He observed that in countries where diets are high in fiber (that is, plant-based diets), there were fewer cases of colon cancer. Around the world, this has proven true. The highest fiber intakes are found in nonindustrialized nations where meat is scarce and plant foods fill the menu. Animal products contain no fiber. The U.S. and other Western nations whose diets are based upon animal products have the highest rates of colon cancer.
While no one is certain exactly how fiber protects against digestive tract disorders, there are several possibilities.
• By definition, fiber cannot be digested by humans early in the digestive process. It moves food more quickly through the intestines, helping to eliminate carcinogens.
• It also draws water into the digestive tract. The water and fiber make fecal matter bulkier, so carcinogens are diluted.
• Bile acids are secreted into the intestine to help digest fat; there, bacteria can change the acids into chemicals that promote colon cancer. Fiber may bind with these bile acids and evict them from the intestines.1 Also, bacteria in the colon ferment the fiber creating a more acidic environment which may make bile acids less toxic.
• Fiber is also protective against other forms of cancer. Studies have shown that stomach cancer and breast cancer are less common on high-fiber diets.2,3 Fiber affects levels of estrogens in the body. Estrogens are normally secreted into the intestine, where the fiber binds with the hormone and moves it out of the body.4 Without adequate fiber, the estrogen can be reabsorbed from the intestine into the bloodstream. High levels of estrogen are linked to a higher risk of breast cancer.
Recommended fibre dosage
In the U.S., the average daily fiber intake is 10 to 20 grams per day. Experts recommend 30 to 40 grams per day.
Sources of fiber
whole grains, beans, peas, lentils, vegetables, and fruits. Foods that are closest to their natural state, unrefined and unpeeled, are highest in fiber.
Fat Raises Cancer Risks
Cross-cultural studies have revealed that the populations with the highest levels of fat consumption are also the ones with the highest death rates from breast and colon cancer. The lowest rates are in groups with the lowest consumption of fats. Migration studies help to rule out the influence of genetics.
Many studies indicate that fat in foods increases one's risk for cancer, and it may also adversely affect breast cancer survival rates for those who have cancer.
Although the total amount of fat one eats is of concern, there is evidence that animal fat is much more harmful than vegetable fat. One study noted a 200 percent increase in breast cancer among those who consume beef or pork five to six times per week.
Dr. Sheila Bingham, a prominent cancer researcher form the University of Cambridge, notes that meat is more closely associated with colon cancer than any other factor. Meat and milk are also linked to both prostate and ovarian cancers.
How Fat Affects Cancer Risks
• It increases hormone production and thus raises breast cancer risks.
• It also stimulates the production of bile acids which have been linked to colon cancer.
The average diet in the United States is about 37 percent fat. The National Cancer Institute suggests that people lower that percentage down to 30 percent; however, studies have shown that fat intake should be well below 30 percent to have an anti-cancer affect. Ten to 15 percent is more likely to be helpful.
The Importance of Vegetables
Not only are vegetables low in fat and high in fiber, they also contain many cancer-fighting substances.
Carotenoids, the pigment that gives fruits and vegetables their dark colors, have been shown to help prevent cancer.
Beta-carotene, present in dark green and yellow vegetables, helps protect against lung cancer and may help prevent cancers of the bladder, mouth, larynx, esophagus, breast, and other sites.
Vegetables such as cabbage, broccoli, kale, turnips, cauliflower, and Brussels sprouts contain flavones and indoles which are thought to have anti-cancer activities.
Vitamin C, found in citrus fruits and many vegetables, may lower risks for cancers of the esophagus and stomach. Vitamin C acts as an antioxidant, neutralizing cancer-causing chemicals that form in the body. It also blocks the conversion of nitrates to cancer-causing nitrosamines in the stomach.
Selenium is found in whole grains and has the same antioxidant effects as vitamin C and beta-carotene. Vitamin E also has this effect. Caution is advised in supplementing selenium, which is toxic in large doses.
Alcohol
Excessive intake of alcohol raises one's risks for cancers of the breast, mouth, pharynx, and esophagus. When combined with smoking, these risks skyrocket. It also raises risks for stomach, liver, and colon cancers.
CONCLUSION
Vegetarians Are Better Off
All the evidence points to a low-fat, high-fiber diet that includes a variety of fruits, vegetables, whole grains, and beans, as being the best for cancer prevention. Not surprisingly, vegetarians, whose diets easily meet these requirements, are at the lowest risk for cancer. Vegetarians have about half the cancer risk of meat-eaters.
Vegetarians have higher blood levels of beta-carotene. They consume more vitamin C, beta-carotene, indoles, and fiber than meat-eaters. Vegetarians also have stronger immune systems. German researchers recently discovered that vegetarians have more than twice the natural killer cell activity of meat-eaters. Natural killer cells are specialized white blood cells that attack and neutralize cancer cells. Also, vegetarians tend to eat more soy products than meat-eaters. Soybeans contain many substances that are anticarcinogens, including lignans and phytoestrogens. A diet that is rich in soybeans may be one reason for the lower incidence of breast cancer in Asia.
A cancer prevention diet is one that is high in fiber, low in fat (especially animal fat), and includes generous portions of fruits and vegetables. It also minimizes or excludes alcohol. The best diets are pure vegetarian diets.
Cancer Facts - Foods for Cancer Prevention
Of the many diseases that affect people these days, cancer is among the most feared. But despite a wealth of scientific data, most people remain unaware of how they can reduce their risk of developing cancer. According to the National Cancer Institute, as much as 80 percent of all cancers are due to identified factors, and thus are potentially preventable. Thirty percent are due to tobacco use, and as much as 35 percent to 50 percent are due to foods. It is easy to control these and other risk factors.
What Is Cancer?
Cancer begins as a single abnormal cell that begins to multiply out of control. Groups of such cells form tumors and invade healthy tissue, often spreading to other parts of the body.
Carcinogens are substances that promote the development of cancerous cells.
They may come from foods, from the air, or even from within the body. Most carcinogens are neutralized before damage can occur, but sometimes they attack the cell's genetic material (DNA) and alter it. It takes years for a noticeable tumor to develop. During this time, compounds known as inhibitors can keep the cells from growing. Some vitamins in plant foods are known to be inhibitors. Dietary fat, on the other hand, is known to be a promoter that helps the abnormal cells grow quickly.
Fiber Fights Cancer
In 1970, British physician Dennis Burkitt observed that a high-fiber diet reduces diseases of the digestive tract. He observed that in countries where diets are high in fiber (that is, plant-based diets), there were fewer cases of colon cancer. Around the world, this has proven true. The highest fiber intakes are found in nonindustrialized nations where meat is scarce and plant foods fill the menu. Animal products contain no fiber. The U.S. and other Western nations whose diets are based upon animal products have the highest rates of colon cancer.
While no one is certain exactly how fiber protects against digestive tract disorders, there are several possibilities.
• By definition, fiber cannot be digested by humans early in the digestive process. It moves food more quickly through the intestines, helping to eliminate carcinogens.
• It also draws water into the digestive tract. The water and fiber make fecal matter bulkier, so carcinogens are diluted.
• Bile acids are secreted into the intestine to help digest fat; there, bacteria can change the acids into chemicals that promote colon cancer. Fiber may bind with these bile acids and evict them from the intestines.1 Also, bacteria in the colon ferment the fiber creating a more acidic environment which may make bile acids less toxic.
• Fiber is also protective against other forms of cancer. Studies have shown that stomach cancer and breast cancer are less common on high-fiber diets.2,3 Fiber affects levels of estrogens in the body. Estrogens are normally secreted into the intestine, where the fiber binds with the hormone and moves it out of the body.4 Without adequate fiber, the estrogen can be reabsorbed from the intestine into the bloodstream. High levels of estrogen are linked to a higher risk of breast cancer.
Recommended fibre dosage
In the U.S., the average daily fiber intake is 10 to 20 grams per day. Experts recommend 30 to 40 grams per day.
Sources of fiber
whole grains, beans, peas, lentils, vegetables, and fruits. Foods that are closest to their natural state, unrefined and unpeeled, are highest in fiber.
Fat Raises Cancer Risks
Cross-cultural studies have revealed that the populations with the highest levels of fat consumption are also the ones with the highest death rates from breast and colon cancer. The lowest rates are in groups with the lowest consumption of fats. Migration studies help to rule out the influence of genetics.
Many studies indicate that fat in foods increases one's risk for cancer, and it may also adversely affect breast cancer survival rates for those who have cancer.
Although the total amount of fat one eats is of concern, there is evidence that animal fat is much more harmful than vegetable fat. One study noted a 200 percent increase in breast cancer among those who consume beef or pork five to six times per week.
Dr. Sheila Bingham, a prominent cancer researcher form the University of Cambridge, notes that meat is more closely associated with colon cancer than any other factor. Meat and milk are also linked to both prostate and ovarian cancers.
How Fat Affects Cancer Risks
• It increases hormone production and thus raises breast cancer risks.
• It also stimulates the production of bile acids which have been linked to colon cancer.
The average diet in the United States is about 37 percent fat. The National Cancer Institute suggests that people lower that percentage down to 30 percent; however, studies have shown that fat intake should be well below 30 percent to have an anti-cancer affect. Ten to 15 percent is more likely to be helpful.
The Importance of Vegetables
Not only are vegetables low in fat and high in fiber, they also contain many cancer-fighting substances.
Carotenoids, the pigment that gives fruits and vegetables their dark colors, have been shown to help prevent cancer.
Beta-carotene, present in dark green and yellow vegetables, helps protect against lung cancer and may help prevent cancers of the bladder, mouth, larynx, esophagus, breast, and other sites.
Vegetables such as cabbage, broccoli, kale, turnips, cauliflower, and Brussels sprouts contain flavones and indoles which are thought to have anti-cancer activities.
Vitamin C, found in citrus fruits and many vegetables, may lower risks for cancers of the esophagus and stomach. Vitamin C acts as an antioxidant, neutralizing cancer-causing chemicals that form in the body. It also blocks the conversion of nitrates to cancer-causing nitrosamines in the stomach.
Selenium is found in whole grains and has the same antioxidant effects as vitamin C and beta-carotene. Vitamin E also has this effect. Caution is advised in supplementing selenium, which is toxic in large doses.
Alcohol
Excessive intake of alcohol raises one's risks for cancers of the breast, mouth, pharynx, and esophagus. When combined with smoking, these risks skyrocket. It also raises risks for stomach, liver, and colon cancers.
CONCLUSION
Vegetarians Are Better Off
All the evidence points to a low-fat, high-fiber diet that includes a variety of fruits, vegetables, whole grains, and beans, as being the best for cancer prevention. Not surprisingly, vegetarians, whose diets easily meet these requirements, are at the lowest risk for cancer. Vegetarians have about half the cancer risk of meat-eaters.
Vegetarians have higher blood levels of beta-carotene. They consume more vitamin C, beta-carotene, indoles, and fiber than meat-eaters. Vegetarians also have stronger immune systems. German researchers recently discovered that vegetarians have more than twice the natural killer cell activity of meat-eaters. Natural killer cells are specialized white blood cells that attack and neutralize cancer cells. Also, vegetarians tend to eat more soy products than meat-eaters. Soybeans contain many substances that are anticarcinogens, including lignans and phytoestrogens. A diet that is rich in soybeans may be one reason for the lower incidence of breast cancer in Asia.
A cancer prevention diet is one that is high in fiber, low in fat (especially animal fat), and includes generous portions of fruits and vegetables. It also minimizes or excludes alcohol. The best diets are pure vegetarian diets.
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