Utilization of Some Sugar Industrial by- Products and Fructan Storing Crops for Bioproduction of Citric Acid

Abstract

Two sugar industrial by-products, cane bagasse SCB and sugar beet molasses SBM along with two fructan storing crops ,chicory roots CR and Jerusalem artichoke tubers JA , alone or after mixing were utilized as a carbon source in fermentation medium to produce citric acid by Aspergillus niger strain GQ890276. It was found that the proximate composition and total sugars content of these agro-materials played a role in terms of citric acid production . Moisture ranged from 6.55 to 23.15%; crude fat from zero to 1.55%; crude protein from 3.27 to 8.53%; crude fiber from zero to 47.46% , ash from3.29 to 8.93% ,nitrogen free extract from 44.83 to 87.06 % and total sugar 8.11 to 87.06% among these materials. The fermentation media either containing mixture of CR +SCB and/or CR as carbon source gave high citric acid yield after 7 days of fermentation comparing with other used carbon sources. The citric acid yield was 59.36 g/L in CR +SCB medium .It was 87.80% when calculation was based on the amount of consumed fermentable sugars. Also this media gave the high biomass ( 22.90 g/L) yield.