Biodegradation of orange peel waste by Lactiplantibacillus plantarum S61: In vitro and In Silico evaluation of antioxidant and antifungal activities of the fermented products

This study explores the potential use of mesocarp from orange peel waste (OPW) as a substrate, used as the sole carbon source in a modified medium Man Rogosa Sharp (MRS), for biotransformation by the Lactiplantibacillus Plantarum S61, and compare it to using glucose conventionally. The focus is on producing antioxidant and antifungal compounds. OPW was used as the sole carbon source in the MRS medium. The medium was inoculated with 1% (v/v) of L. plantarum S61 at a concentration of 106 (cfu/mL) and incubated at 37°C for six days. The results showed that L. plantarum S61 had significant growth with OPW and glucose. The pH change was less severe with OPW, it decreased from 6 to 4.3 with glucose and decreased from 5.9 to 5.2 with OPW as the sole carbon source. The decrease in surface tension observed during the fermentation was -0.76 ± 0.7 mN/m and -0.33 ± 0.61 mN/m in the presence of glucose an OPW, respectively. The fermented OPW showed substantial antioxidant and anti-Rhodotorula glutinis UMP22 activities, exhibiting inhibition diameters of approximately 21.06 ± 0.68 mm, and 20.5 ± 0.88 mm in the presence of glucose and OPW, respectively. These findings demonstrate the potential of L. plantarum S61 for the biotransformation of OPW into valuable compounds. This research suggests that L. plantarum S61 holds promise as a bioresource for the biotransformation of OPW into valuable compounds, which could find applications in the food and healthcare industries.