Monthly archives: December, 2011

Citric Acid

Almost all of the world’s output of citric acid, an intermediate in tricarboxylic acid cycle, is produced microbiologically. Citric acid cycle is a food preservative and flavoring agent of fruit juices, candy, ice cream, marmalade and other products. It is also used in pharmaceuticals as an iron chelator (binder), as a preservative for store blood, …

Ethanol

Ethanol can be produced chemically from petroleum or microbiologically from fermentable carbohydrates. It is produced in the anaerobic fermentation of glucose by Saccharomyces cerevisiae. Corn & other material must undergo saccharification before they can be fermented. The carbohydrate in corn starch is enzymatically released by treating the ground corn with a amylase and gluco-amylase. Molasses …

Vinegar

Vinegar literally means ‘sour wine’. It is manufactured by the bacterial oxidation of ethanol in fermented wine, beer or cider and used as a condiment and preservative. The initial step is the fermentation of wine by varieties of S.cerevaciae. This leads to the formation of ethanol which is a prolonged reaction. After completion of fermentation, …

Yoghurt Production

 A form of fermented milk has been produced in most countries where milk is drunk., incubation takes 12 hours at 32o to reach the set state of natural yoghurt. The popularity of the product is increased by the addition of sugar and fruit to disguise the acidity. Yoghurt is a nutritious dessert and its manufacture …

Manufacture of Cheese

Traditional cheese making depended on the natural micro-organisms present in the dairy and milk. Microbes sour that milk, producing lactic acid and lowering the pH, so that when rennet (from the stomach of young mammals) was added, the milk curdled and separated into solid curds and liquid why (which was used as a substitute for …

Plant Tissue Culture Media

Different plant parts require different nutrients for their healthy development. So it is important to formulate a medium for plant cell growth which can support the requirements of different organelles of a cell as well as diverse cell types corresponding to each tissue type. Coconut water was used by Van Overbeek in 1941 allowed the …

Requirements in Plant Tissue Culture

1) Lot of good quality water (distilled & double distilled water) which does not contain salts or any contaminants. 2) Waste water should be properly processed before it is discarded to the environment. 3) Laminar air flow is required to perform aseptic operations. 4) Facilities like A/C, light source, Humidity regulator should be available for …

Electron Transport in Photosynthesis

Photosynthesis of prokaryotic cyanobacteria as well as that of eukaryotic algae and higher plants produces oxygen and the basic process is similar in them all. A form of the Hill and Bendall ‘Z’ scheme of the sequence of processes and electron transport leading from water-splitting through NADP+ reduction is explained below. Photon capture by the …

Internal structure of Chloroplast

Electron microscopy shows the chloroplast to consist of an envelope enclosing a complex of membranes, the thylakoid system often joined or stacked into grana; the lipid membranes, contrast with the background when stained with lipophilic electron dense osmium. The space between the envelope and thylakoid membranes is the chloroplast stroma. The envelope is composed of …

Plant Cells

The entire genomic DNA cannot express at a time. In this process only particular type of gene is expressed at a time, specifically leading to the production of a particular gene product which is in turn specific for a plant organ or tissue. These specific genes are responsible for the special characteristics like smell, taste, …

Photosystems

The Concept of two photosystems originated in the work of Emerson & Lewis in 1943. Working on the action spectrum  for the pigments of Chlorella (a green alga), they found that at 440-520 nm, there was very little evolution of oxygen. This is quite understandable because those wavelengths of light are absorbed by carotenoids and …