“Biotech” (BT) conjures an image of cutting edge research undertaken in sterile high tech labs, the products of which rarely concern the common man. But, contrarily, BT has been in the public consciousness for many reasons and also since antiquity – that belies its cutting edge image. For example, the common process of converting milk to curd is BT, or the process of making dosa batter sour.
In general, “technology” refers to the application of science. In the same vein, Biotech or Biotechnology is “any technological application that uses biological systems, living organisms, or derivatives thereof, to make or modify products or processes for specific use” – as defined by the UN. The “biotech” in the conversion of milk to curd involves the use of bacteria to break down milk protein into lactic acid.
What is BT?
BT is not a discrete field of study, rather a convenient association of different sciences with biology. This association is driven by the need to find greener alternatives to present processes. And it is evident that the thrust of BT has two directions: firstly to discover organisms that can do biologically what is presently being done chemically, and secondly to modify existing biological agents to improve their efficiency. While there are terms such as industrial BT, textile BT, medical BT, food BT, agricultural BT. etc., to describe the various associations, a more meaningful division could be: red BT, denoting all BT activities that relate to medicine/healthcare; green BT, for all agriculture/food related BT activities; blue BT, includes all activities relating to aquatic applications of BT; and, white BT, referring to all activities relating to BT applications in various industries. We shall see how each of these BT subclasses has impacted us.
The Industrial Revolution, while improving lives, has destroyed environments. Stringent environmental laws and greater awareness have meant that industries need to treat their wastes before disposal, a cost that effects their bottom lines. This has spurred the search for greener alternatives. This search has zeroed in on enzymes. Enzymes are chemicals that are naturally generated by living beings to break down food. Their action is similar to those of catalysts in normal chemical reactions; and being biodegradable they don’t need further treatment before disposal. There are different types of enzymes, and they are classified based on their target molecule. For example lipases are enzymes that aid the breakdown of Lipids or oily substances, celluloses are enzymes that aid the breakdown of cellulose, etc. BT has exploited this natural ability in micro-organisms (MOs), and in many cases enhanced or modified this ability to serve mankind. Some places where BT is applied:
Enzymes are increasingly being used in different processes instead of chemicals. For example, hydrogen peroxide, which is used to bleach cotton, needs to be removed from the fabric before it can be dyed. There are peroxidase enzymes which can do the same job, saving a lot of water which would otherwise have to be used for rinsing. Enzymes also play a role in creating the “stone washed” look in jeans – this was originally created using pumice stones, but no longer. Cotton, being white, needs to be dyed to create textiles of any other color, requiring a lot of chemical dyes. BT cottons that have been genetically modified to express color makes the process of dyeing redundant.
Textile cleaning industry
Stubborn stains can be broken down by specific enzymes; for example, stains left by oily substances can be broken down using lipases. Enzymes that work well at normal room temperatures obviate the need for high temperature and harsh chemicals for the job. In India, premium detergents like Ariel and Surf Excel include enzymes to tackle tough stains without damaging the cloth (or the environment).
Converting wood to paper requires removing lignin from the wood. Fungi produce the laccase enzyme that can breakdown lignin, and is ideal for this job. Another case: in order to make used paper fit for reuse, it needs to be free from glues or other sticky materials. Esterase enzymes that attack the bonds that allow the sticky substance to cling to the pulp are used for the separation. Traditionally, both these steps require treating the pulp with chemicals at a high temperature. With enzymes, the process becomes significantly cleaner and cheaper. Bleaching the pulp to create white paper can be achieved with enzymes called xylanases, instead of the usual chlorine-containing chemicals, reducing the need to treat the waste water.
Plastics have revolutionized our lives, but their recalcitrance to degradation have made them ecologically unacceptable. Bioplastics offer the best of both worlds. These are different from normal plastics in two ways – the raw material and their molecular makeup. Normal plastics use petroleum as the main raw material, and their complex molecular structure makes them resistant to decomposition by micro organisms. Bioplastics, on the other hand, use starch as the raw material – starch is abundant in plants such as corn, potato, etc., which are renewable and easier to obtain. Also, their molecular structure is more simple making them more biodegradable. Just as with normal plastics, there are many types of bioplastics, all with different molecular structures. Polylactic acid (PLA) is a popular bioplastic material. This has its starting material lactic acid that is produced by the enzymatic breakdown of starch. Bioplastics can be molded into different shapes and share the same utility possibilities as regular plastics.
This is the reclaiming of any area that has been polluted beyond human/animal inhabitability, using biological agents. Take the case of cleaning up oil spills. The BT answer to dealing with this challenge is to spray the slick with bacteria that prefer oily environments. These bacteria break up the oil and in the process release carbon dioxide and water, as part of their normal metabolism. The environmental impact of the cleaning up operation is almost nil (some chemicals need to be added to encourage the bacteria to speed up the process), since there are no by-products that are unsafe. Oil slicks are accidental in nature, but normal petroleum extraction and delivery activities involve leakages and spills that taint the vicinity. MOs are also used in these areas to clean up the mess.
These are the subject of a lot of public attention, especially after petroleum prices skyrocketed in the recent past, and also due to concern about global warming. The Jatropha plant has been in the news for being a source of biodiesel – oil derived by crushing its seed is mixed with alcohol to make biodiesel – which is an ideal substitute to diesel. BT offers other avenues of creating substitute fuels such as ethanol (ethyl alcohol), which can also be used in modern vehicles that otherwise run on petrol. The core process involves using appropriate enzymes to break down plant matter to create the ethanol. The plant matter can be plant products such as corn, or sugarcane, or any plant waste product or even wood from trees – the enzyme needed to perform the break down changes with the source. Ethanol can be used as an additive to normal petrol – a mixture of 85 per cent ethanol and 15 per cent petrol has been found usable with minimal engine modification. Biogas/”gobar”gas plants are quite well known here in India, and BT plays a role in the process of using bacteria to break down dung/”gobar” into methane which can then be used as burning fuel.
MOs are used to aid the process of extracting metal from its ore, mostly sulphide ores. This process is used in the extraction of metals such as copper, nickel, gold, zinc, etc. At present, about 25 per cent of the total copper mined uses MOs to extract impurities from the ore before further processing. Gold miners also benefit from using MOs in the extraction process. Algae are used to improve the oil output from oil wells. Once injected into the oil well, algae, as a normal by-product of their metabolism, produce carbon dioxide gas which displaces the petroleum and facilitates recovery
The Green Revolution was powered by chemicals in the form of fertilizers and pesticides. The environmental cost of this reliance on chemicals is only now being appreciated.
Rhizobium bacteria absorb atmospheric nitrogen and makes it available in a form that can be absorbed by plants. Nitrogen is an essential nutrient for plants, and a major component of commercial fertilizers. Rhizobium naturally attaches itself to legumes by forming root nodules, but through BT it is possible to increase the number of such nodules, thus increasing the rate of nitrogen absorption. Similarly, non-leguminous plants are associated with Azetobacter bacteria for nitrogen absorption. All that is needed is for seeds to be coated with these bacteria prior to sowing.
Bacillus thuringiensis is a bacterium that is used as a natural pesticide because it infects many pests, and can be sprayed over crops instead of regular pesticides. Going a step further is Bollgard BT cotton. This is a product of Monsanto Company, and the first GM crop to be planted in India. The Bt in “Bt cotton” stands for Bacillus thuringiensis, which is the source of the gene inserted into the cotton DNA, that causes the production of a protein that is toxic to the pest American Bollworm that destroys cotton balls. This innate resistance reduces the need for pesticides.
Besides plants and MOs, BT has also modified large animals, mainly farm animals such as cows, pigs, goats, etc. High yielding cattle are in demand for selective breeding among dairy farmers; this is an ancient practice which takes a long time to produce results. BT speeds things up by genetic manipulation. Besides improved milk production, the nature of the milk can also be modified. Cows have been genetically modified to carry human genes responsible for the creation of lactoferrin – an iron carrying protein that is essential for infants. The milk produced by these cows is iron-rich in contrast to normal cow milk, making it ideal infant food (to substitute human milk). Spider silk is acknowledged to be the strongest natural fiber, and this has many potential applications where a right mix of strength and weight is needed – bullet proof vests come to mind first. By genetically modifying goats with spider genes, spider silk is produced along with goat’s milk in much larger quantities than can be produced by spiders. Needless to say, the issue of animal rights is a major stumbling block in this area.
The decoding of the human genome has allowed scientists to identify the genetic basis of human susceptibility to many diseases, but the full benefits of these findings are still some time away. Even so, BT has already contributed to healthcare in many ways:
The traditional method of testing for disease involves taking a sample (blood, sputum, etc.) and culturing it over a period of time to allow microbial growth, and then identifying the organisms. This delay has been dramatically reduced by using tests that directly check for unique patterns of proteins or DNA (much like anti-virus software flags suspicious programs). Monoclonal antibody testing is based on the principle of the unique antibody-antigen relation. Polymerase Chain Reaction (PCR) is another BT product that is used to rapidly make copies of genetic material allowing even minute samples to be used for testing. It is the process behind such techniques as DNA fingerprinting which can be used to uniquely identify any living organism. PCR can also be used to test genetic material for identifying disease agents – the test to detect the Swine flu virus (H1N1) is based on PCR. The use of animals as test subjects is controversial, and yet the only way to ensure a drug is fit for human trial. The search for a cancer treatment has benefited from a special type of mouse called Oncomouse or Harvard Mouse, which is a BT product. This GM mouse has a human gene (oncogene) that makes it susceptible to cancers, and hence is an ideal test subject for anti-cancer research.
It has made it possible to generate medicines for human consumption by genetically modifying MOs, and insulin generating MOs have already been mentioned. Other medicines that are BT products include recombinant EPO (Erythropoietin) a protein that is responsible for red blood cell generation. EPO is created on a large scale by inserting the human gene responsible for EPO production to Chinese hamster ovary cells which are then cultured. EPO is the most widely sold BT medicine, and is needed for anemic patients – such as those suffering from kidney failure. We have mentioned the potential uses of bioplastics. In the medical arena, bioplastic surgical thread is used for stitching up surgical wounds. It gradually self dissolves, saving the patient another hospital visit.
Marine organisms have been a source of food and medicines since ancient times. Different forms of algae serve as protein rich food, a source of gelling agents used as additive in ice creams, as lubricants, etc. The wonder properties of Spirulina were the topic of much discussion in the recent past. “The most powerful food in the world.” Spirulina is an algae that is rich in many essential nutrients, proteins, vitamins, iron, etc. Medicines from marine life include a painkiller that is actually a neurotoxin and part of the defense mechanism of cone snails.
Algae are being seen as an important source of biofuels, especially since algae seem to thrive on waste water – irrespective of the source: either from factories, mines or residential complexes.
The future will see greener alternatives replace most, if not all, environmentally unfriendly chemicals and fuels, thanks to BT. Butanol, which is seen as a replacement for petrol, and ethanol are expected to be produced in larger quantities using GM bacteria.
It needs to be noted that unlike most other new products, BT products have a very long gestation period from lab to market, and even then public opinion can drown down scientific reasoning – particularly where food is concerned. So while many interesting concepts are discovered, applied, tried and tested in the lab, they need not survive the trip to the market shelf. Some BT food products in the pipeline: nutrition enhanced food: potatoes containing vaccines against hepatitis virus, rice fortified with vitamins, iron and omega3 fatty acids, etc., drought resistant GM corn – a result of inserting a bacterial gene that imparts resistance to the organism from adverse environments into the corn DNA.
And some wishful thinking doesn’t seem too far-fetched. So far, human genes have been transferred to MOs to enable them to produce human products. In the future, one can expect the reverse – genes coding for the best features of plants and animals transferred into the human, creating a man that can run as fast as a cheetah and fly as well as a bird.