Effect of copper ions on mould morphology and citric acid productivity by Aspergillus niger using molasses based media

Recent Advances in Citric Acid Bio-production and Recovery

“…Studies revealed that CA production by A. niger under submerged fermentation conditions using molasses as the substrate was severely affected by the presence of iron at a concentration as low as 0.2 ppm; however, the addition of copper at 0.1-500 ppm at the time of inoculation or during the first 50 h of fermentation was found to counteract the deleterious effect of iron. Researchers have also reported such beneficial effects of Cu 2+ in counteracting the Fe 2+ effect (Haq et al 2002). Additions of Mn 2+ at concentrations as low as 3 μg/L have been shown to drastically reduce the yield of CA under otherwise optimal conditions (Rohr et al 1996).…”

A screen for Neurospora knockout mutants displaying growth rate dependent branch density

“…As with hyperbranching caused by other factors, the phenotype characteristic of frost was suppressed by the addition of exogenous Ca 2þ (Sone & Griffiths 1999). In Aspergillus niger, the addition of excess Cu 2þ was shown to skew growth towards shorter and highly branched hyphae (Haq et al 2002).…”

Citric acid production by recycling its wastewater treated with anaerobic digestion and nanofiltration

“…However, the citric acid industry is facing the problem of wastewater handling. In the traditional citric acid production process, wastewater with high chemical oxygen demand (COD, 15,000-20,000 mg/L) and low pH (4.0-4.8) is produced at the rate of 50-60 ton/ton citric acid [5]. The wastewater is usually treated by anaerobic-aerobic digestion and further treatment by municipal sewage plant to meet the national discharge standard [6][7].…”