This review paper from 2020 highlights the key features of sustainability improvement involved in citric acid production,
References:
Amato A, Becci A, Beolchini F. Citric acid bioproduction: the technological innovation change. Crit Rev Biotechnol. 2020 Mar;40(2):199-212. doi: 10.1080/07388551.2019.1709799. Epub 2020 Jan 5. PMID: 31903797.