[continued from previous message]   
      
   What else can we use to produce biofuel?   
      
   Two leading strategies involve ethanol production from the   
   degradation of cellulosics, and biodiesel production from algae.   
      
   The common alcohol, ethanol, has been harnessed by humans for   
   millennia, made through the microbial conversion of biomass   
   materials, typically sugars, through fermentation. The process   
   starts with a solution of fermentable sugars, fermented to   
   ethanol by microbes, and then the ethanol is separated and   
   purified by distillation.   
      
   Fermentation involves microorganisms, typically yeasts, that   
   evolved billions of years ago before Earth’s atmosphere   
   contained oxygen, to use sugars for food and in the process   
   produced ethanol, CO2 and other byproducts:   
      
   (sugar) C6H12O6  ?  2 CH3CH2OH + 2 CO2   (ethanol + carbon   
   dioxide)   
      
   Microorganisms typically use 6-carbon sugars and their   
   precursors, glucose and sucrose. But because sugars and starches   
   are foods, a better alternative for ethanol production should be   
   from non-food cellulosic materials, such as paper, cardboard,   
   wood, and other fibrous plant material. Switchgrass and napier   
   grass have been studied extensively as the best alternatives.   
      
   Cellulosics are abundant and much of the supply is considered   
   waste. Cellulosics are comprised of lignin, hemicellulose, and   
   cellulose. Lignin provides structural support for the plant and   
   encloses the cellulose and hemicellulose molecules, making it   
   more difficult to process for fuel.   
      
   Thus, efficiently making ethanol out of cellulosics requires a   
   different approach than for corn.  They can either be reacted   
   with acid (sulfuric is most common), degraded using enzymes   
   produced from microbes, or heated to a gas and reacted with   
   chemical catalysts (thermo-chemical). Each has its variations,   
   some can be combined, and all are attempting to be   
   commercialized. Still, these processes are stuck at about twice   
   the price per gallon produced compared to corn. Recently,   
   special microorganisms have been genetically engineered to   
   ferment these materials into ethanol with relatively high   
   efficiency.   
      
   It’s no wonder we just went with corn!   
      
   Another less discussed biofuel strategy is biodiesel replacing   
   petroleum diesel. Biodiesel is made by combining almost any oil   
   or fat with an alcohol such as ethanol or methanol.   
      
   Biodiesel can be run in any diesel engine without modification   
   and produces less toxic emissions and particulates than   
   petroleum diesel.  It causes less wear and tear on engines, and   
   increases lubricity and engine efficiency, and releases about   
   60% less CO2 emissions than petroleum diesel.   
      
   Rudolf Diesel originally developed the diesel engine to run on   
   diesel from food oils such as peanut and soybean, but animal   
   fats and any other natural oil can be used.  However, almost a   
   hundred years ago, the need for fuel outstripped the supply of   
   natural oils and petroleum become the only abundant source   
   available.   
      
   The most common natural oils used are rapeseed and canola oil,   
   but a particularly promising candidate is oil from algae. Algae   
   production uses non-productive land and brine water and produces   
   over 20 times the oil production of any food crop. An acre of   
   algae can produce almost 5,000 gallons of biodiesel. It does not   
   compete with food crops for arable land or potable water and   
   could produce over 60 billion gallons/yr that would replace all   
   petroleum-based diesel in the U.S.   
      
   However, all algae production facilities presently sell their   
   crops to the food and cosmetic industry at a much greater profit   
   than they would get from the fuel industry.   
      
   I guess for biofuels, as for any other source, there’s just no   
   such thing as a free lunch.   
      
   [Note: Thanks to Eric and other commenters for pointing out some   
   errors, especially my failing to mention the tax credits and   
   tariffs have expired]   
      
      
   http://www.forbes.com/sites/jamesconca/2014/04/20/its-final-corn-   
   ethanol-is-of-no-use/   
      
        
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)