sp. ZB is a cell factory for the production of gibberellic acid using a cheap substrate in solid state fermentation.

Gibberellic acid from the fungi has been widely used in agriculture. In this study, more than 20 fungal isolates were screened and sp. ZB shown to produce more gibberellic acid than other fungal isolates. Cow dung was used as low cost substrate for gibberellic acid production in solid state fermentation (SSF). Carbon, nitrogen and ionic sources stimulated gibberellic acid production in SSF. Lactose emerged as the significant carbon source supporting more gibberellic acid production (731 µg/g). Among the nitrogen sources, glycine appeared to influence the production of more gibberellic acid (803 µg/g). The process parameters were optimized to enhance gibberellic acid production using a two-level full factorial design and response surface methodology. The amount of gibberellic acid production was influenced mainly by moisture and pH of the substrate. Gibberellic acid production was 1312 µg/g under the optimized conditions and the predicted response was 1339 µg/g. The gibberellic acid yield increased twofolds after medium optimization. The extracted gibberellic acid was sprayed on the growing Mung bean plant and it stimulated the growth of the plant effectively. To conclude, cow dung is a new alternative to produce gibberellic acid in SSF.