Citric Acid Production by Aspergillus niger and Trichoderma viride Using Hydrolysed Potato Peels Substrate

Aim: Production of citric acid by Aspergillus niger and Trichoderma viride isolated from soil in Keffi, Nigeria using Hydrolysed potato peels substrate.

Place and Duration of the Study: This study was carried out in the Department of Microbiology Faculty of Natural and Applied Sciences Nassarawa State University Keffi, Nigeria, between February and July 2017.

Methodology: Aspergillus niger and Trichoderma viride were isolated from soil in Keffi and identified using standard microbiology methods. Hydrolysed potato peels substrate - soy beans cake (ps) and potato peel - groundnut cake (pg) production media were prepared by following standard fermentation conditions. The citric acid produced was estimated using Gas Chromatography/Mass Spectrometry (GC/MS) method respectively.

Results: At pH 5.5 after 72 hours of incubation the highest production of citric acid was produced by T. viride 176.33±20.10 mg/l on ps and A. niger 91.11±21.22 mg/l on ps. At pH 6.0 T. viride produced highest on ps 211.40±7.10 mg/l and A. niger 170.22±10.81 mg/l on ps while at pH 6.5 A. niger produced highest 181.09±20.8 mg/l on ps and T. viride 98.76±19.8 mg/l on ps with highest total Sugar consumption and dry cell mass were 16.19±20.01 g/l and 13.17±1.04 g/l while after 144 hours of incubation at pH 6.0 A. niger produced highest citric acid 404.53 ± 14.32 mg/l on ps and T. viride produced 297.60±8.31mg/l on ps highest total Sugar consumption and dry cell mass were 19.91±2.01g/l and 17.0±15.11 g/l.

Conclusion: The maximum citric acid production obtained during the course of study was 404.53±14.32 mg/l on ps by A. niger and at pH 6.0. Also potato peels showed that it can be alternative carbon source for citric acid production as cheaper source of carbon.