XANTHAN FERMENTATION OF CITRUS WASTE

Four different fractions of citrus waste were compared as substrates f or xanthan fermentation: whole citrus waste, pectic, hemicellulosic an d cellulosic extracts. The whole waste was found to be a good substitu te for glucose media for xanthan production. Xanthomonas campestris ut ilized both simple and complex carbon compounds originating from citru s wastes. Substrate utilization in the medium based on pectin extract was similar to that in the medium based on a whole citrus waste and th e pectic extract yielded the same amount of xanthan as the whole waste . This indicated that water-soluble substances in citrus waste such as pectins, organic acids and simple carbohydrates were readily converte d into xanthan and that they were the main contributor to xanthan prod uction from the whole waste. The biodegradabilities of the hemicellulo se and cellulose extracts were found to be much lower than that of the pectic extract.