Biosynthesis of Vitamin B12 and Bioactive Components through Microbial Fermentation of Fish Byproducts

Azka Tauqeer
MSc
Department of Biochemistry

Date: Aprl 7, 2025
Time: 1:00 p.m. to 2:00 p.m. 
Room: CSF 1302

Abstract:

The seafood industry generates over 20 million tons of fish byproducts annually, leading to environmental and economic concerns. While some byproducts are processed into fishmeal, fertilizer, or oil, a significant portion remains unused. Our study explores microbial fermentation as a sustainable method to upcycle fish waste into valuable nutrients and bioactive compounds. One such compound is vitamin B12, which is industrially produced through bacterial fermentation of molasses and corn steep liquors. Fish byproducts, being a rich source of several macro- and micronutrients, present a cost-effective, sustainable alternative for synthesizing value-added products. This study uses Pseudomonas denitrificans, a known B12 producer and Lactobacillus plantarum, a lactic acid bacterium, to ferment fish waste and produce vitamin B12, along with potential bioactive compounds. Fish byproducts were homogenized, autoclaved, and fermented with L. plantarum LP39 and P. denitrificans RH 926 strains. Microbial growth was assessed via colony-forming unit (CFU/mL) counts and doubling time calculations. Fermentation was initially conducted at fish waste concentrations of 10, 20, 25, and 50%. Response Surface Methodology (RSM) was applied to optimize fermentation conditions, using concentrations and fermentation time as independent factors. Vitamin B12 content in the fermented products was quantified using Ultrahigh-Performance Liquid Chromatography-Orbitrap Mass spectrometry (UHPLC-Orbitrap-MS), followed by untargeted metabolomics to screen for bioactive compounds.  We found that the doubling times for P. denitrificans and L. plantarum were 50.4 and 56 minutes, respectively. Both bacteria grew rapidly, peaking at 24 hours before declining, following typical microbial growth patterns. RSM analysis predicted optimal microbial growth at 23% fish byproduct concentration and 22.5 hours of fermentation. Our preliminary findings suggest the suitability of fish byproducts for microbial growth, leading to biotransformation of nutrients. The upcycling of these byproducts has potential, applications in food, health, and nutraceutical industries.