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This investigation aimed at production of gluconic acid by fungal species isolated from soil in Keffi. Standard microbiological methods were employed for isolation and identification of the fungal isolates. The yields of gluconic acid produced by the different isolates of the fungi were determined using gas chromatograph and mass Spectrometry. The occurrence of fungi showed thatRhizopus oryzaewas 100%,Aspergilluscarneuswas 75.0%,Aspergillusnigerwas 75.0% andAspergillusterreuswas 100% whileTrichoderma viridewas 25.0% andFusarium moniliformewas 25.0%. The result further demonstrated that three species of the fungal isolatesAspergillusniger, AspergilluscarneusandFusarium moniliformewere found to produce gluconic acid. Screening for gluconic acid production showed thatAspergilluscarneusisolated from locations As1, Cs1 and Cs2,Aspergillusnigerisolated from locations Bs1, Bs2 and Cs4 were able to produce gluconic acid. Result of effect of temperature, pH, substrate concentration and fermentation time on production of gluconic acid showed that AspergillusnigerBs2 produced highest amount of gluconic acid at 28oC, similarly highest amount for gluconic acid produced byAspergilluscarneusAs1 was at 28oC, whereasFusarium moniliformeBs4 produced highest at 30OC. pH 6.5 was found to the best optima pH for production of both gluconic acid for the fungi studied namelyAspergillusnigerBs2 andAspergillus carneusAs1 andFusarium moniliformeBs4 produced highest gluconic acid at pH 5.5. The substrate concentration showed highest production of gluconic acid was produced byAspergillusnigerBs2 at substrate concentration of 25%.AspergilluscarneusAs1 produced highest at substrate concentration of 20% andFusarium moniliformeBs4 produced highest at substrate concentration of 20%. The fermentation time showed highest production of gluconic acid by AspergillusnigerBs2 andAspergilluscarneusAs1 was after 144 hours whereasF.moniliformeBs4 produced gluconic acid after 120hrs respectively. The fungi species isolated from soil in keffi revealed great ability in production of gluconic acid. |
