Authors: Sunil Kumar Behera Prangya Parimita Panda Sandeep Kumar Saini Nilotpala Pradhan Lala Behari Sukla Barada Kanta Mishra
Publish Date: 2012/11/17
Volume: 30, Issue: 2, Pages: 392-399
Abstract
Oxalic acid is a prominent metabolite secreted by several fungi under specific conditions which acts as a metal chelating agent Amongst different fungal species Aspergillus niger is favored as the best option for microbial production of oxalic acid The present study deals with the oxalic acid over production by A niger in response to manganese supplement to its growth medium which in turn improves the recovery of nickel from pretreated chromite overburdenCOB during fungal bioleaching The metabolic pathway in oxalate biosynthesis by A niger involves one prominent cytoplasmic enzyme oxaloacetate acetylhydrolase OAH which catalyzes the breakdown of oxaloacetate metabolic intermediate to oxalate and acetate Oxalic acid production was increased due to supplement of manganese to the culture medium of the A niger Manganese acts as cofactor for OAH enzyme further it enhances the catalytic activity of OAH to produce more oxalate With oxalic acid production by A niger nickel recovery from pretreated COB was improved During the study a maximum of nickel recovery was achieved up to 386 from pretreated COB by adding 80 ppm of manganese to the culture media whereas 240 of nickel was recovered without supplement of manganese experiments were performed at 30 °C and the COB pulp density 2 w/v
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