Assessment of solid state fermentation by a biolectronic artificial nose.

The use of a bioelectronic artificial nose (AN) is described for on-site-monitoring to assess the reaction patterns of solid state fermentations for control of microclimate at sampling site. The nose consists of fractionated olfactory cell proteins of bullfrog (as a receptor membrane) coated on a piezoelectric quartz crystal connected to an oscillator and a data recorder with a personal computer (PC). Five fractions of the olfactory cell proteins gave 5 probes. The response of the nose was analyzed by the PC either as profiles to show the kinds of doors, or as scale factors to show the intensity of odours. Definite differences were noted between the profiles of the headspace gases from earlier and later stages of composing of solid hog wastes. The scale factors showed a single large peak in the earlier stage and one small peak in the later stage. The former showed vigorous biodegradation of organic matter and the latter indicated stabilization of the finished compost. In addition to its use in composing, the nose can discriminate various kinds of alcoholic beverages.