A sustainable method and system for producing bio-fuels from citrus peels and the recovery of limonene and pectin prior to fermentation of the peel solids. The light guide plate has an incidence side face opposite to which the primary light source employing LEDs or the like is disposed, an emission face for emitting light, which has been incident to the incidence side face, during the propagation process, and a back face oppositely located with respect to the emission face. A pharmaceutical preparation and a reagent are described which contain the said protease andor its proenzyme. The bone anchors are threaded into the vertebrae and have a reduced diameter leading end which the locking screws expand to lock the anchor in the vertebrae and secure the end of the locking screw in the anchor. The invention also includes a method for purifying the non-ionic contrast agents. In order to suppress sulfate formation, at least a portion of the loaded metal is complexed with at least one of sulfate, phosphate, and carbonate.