“…Among the various organic acids produced by fungi, citric acid has been by far the most important in economic terms (Zidwick, 1992), with an estimated world annual production o f 400,000 tons (Roehr et al, 1992 as referenced by Gadd, 1999), and therefore, it is one o f the most important fermentation products currently manufactured (Harvey and McNeil, 1994). The primary use o f citric acid is in the food industry, while citric acid has been demonstrated by many investigators to complex heavy metals due to the electron-donor groups in its structure.…”