Mutant strains of Penicillium chrysogenum PL501 grown on selected agro wastes: a prospect for higher production of penicillin in Nigeria

Selected agro wastes found in Nigeria (cassava shavings, corncob, sawdust, and sugarcane pulp) were compared with glucose and lactose as microbial substrates for cultivating an indigenous strain of P. chrysogenum (PL 501) and antibiotic production. In the growth studies, corn cob and cassava shavings significantly (p < 0.05) produced the highest amount of mycelia weight. Corn cob yielded a mycelia weight of 0.15 ± 0.02 and 0.92 ± 0.04mg/ml on the 3 rd and 9 th day respectively, while cassava shavings yielded a mycelia weight of 0.13± 0.07 and 0.12± 0.02mg/ml on the 3 rd and 12 th day respectively. Mycelia weight of the organism, in media containing glucose, sugar cane and lactose was 0.12 ± 0.02, 0.068 ± 0.05 and 0.055± 0.03mg/ml respectively, was highest on the 9 th day. Sawdust gave the least growth with a mycelia growth of 0.07 ± 0.01mg/ml on the 3 rd day. Changes in extracellular protein secreted into the different media (every 3 days for 21 days) show that culture media containing cassava peels gave the highest protein peak of 0.38 ± 0.08 mg/ml on the 6 th day, while corncob gave an early peak of 0.30 ± 0.03mg/ml on the 3 rd day. Sawdust gave two protein peaks, 0.15 ± 0.03 on the 3 rd day and 0.25 ± 0.01mg/ml on the 12 th day. A total protein yield of 0.2 ± 0.05, 0.08 ± 0.02, 0.06 ± 0.02 mg/ml respectively was obtained with glucose, sugarcane pulp and lactose containing media on the 3 rd day. Penicillin production was highest in media enriched with sugarcane pulp (8.65 ± 0.02μg/ml) and cassava shavings (6.85 ± 0.05μg/ml) followed by corncob (5.54 ± 0.01μg/ml) and sawdust (2.23 ± 0.02μg/ml) when compared to commercial synthetic glucose (7.68 ± 0.03μg/ml) and lactose (5.32 ± 0.05μg/ml). The results suggest that these agro wastes could serve as cheap fermentation substrates for growth of fungus and penicillin production. Mutation of organism produced two mutant strains with 70% penicillin yield more than the parent strain