Riboflavin producing bacteria

Riboflavin is an essential, water-soluble vitamin (B2) and a component of basic cellular metabolism. Ten different riboflavin enriched food sources were collected from Vellore district. Totally 72 bacterial strains were isolated and cultured on nutrient agar plates. Out of these, 43 strains were identified as riboflavin producers. Isolated bacterial strains HDS27, HDS07, HDS14, HDS18, HDS38 and HDS54 isolated from milk, mushroom, spinach, lamb kidney, beef liver and mackerel fish were found to be potent riboflavin producers.

Based on morphological, biochemical and molecular characterization, the potent strains were identified as Lactobacillus plantarum (HDS27), Bacillus cereus (HDS07), Delftia tsuruhatensis (HDS14), Citrobacter freundii (HDS18), Enterobacter cloacae (HDS38) and Bacillus cereus (HDS54). The selected potent isolates HDS27 from milk and HDS07 from mushroom showed a maximum riboflavin production of 3.69 mg/L and 2.9mg/L respectively. These potent strains could be a better starter for substituting the conventional bacteria for large scale production of riboflavin in industry.

Benefits of Riboflavin

Riboflavin transporter deficiency (RTD) is a progressive inherited neuropathy of childhood onset, characterised by pontobulbar palsy, sensorineural deafness, sensory ataxia, muscle weakness, optic atrophy and respiratory failure. Riboflavin supplementation is beneficial in short-term reports, but the quantum of benefit in various clinical domains is not well understood.

Information on the clinical and functional status before and after riboflavin supplementation was collected and analysed. Seventy-six of the 94 patients (80.9%) showed an overall improvement after riboflavin supplementation, and the remaining (19.1%) were stable, though some patients had deteriorations in individual domains with no reported deaths. The domains that had the highest rates of response to riboflavin supplementation were gross motor function (93.3% improved), bulbar palsy (91.3%) and ataxia (90.0%). Improvements were also seen in limb muscle weakness, audiology, facial nerve palsy and respiratory function. Despite treatment, many patients required assistance to ambulate and had severe or profound hearing loss and some remained gastrostomy or tracheostomy dependent. Riboflavin supplementation is a lifesaving intervention for patients with RTD and results in a profound improvement in several functional domains, with early diagnosis and treatment further improving outcomes. Despite treatment, patients are left with residual disability. There is a need to accurately measure functional outcomes in children with RTD and develop additional disease-modifying therapies.

Targeted Drug Delivery

It has been shown that riboflavin transporters and the riboflavin carrier protein are overexpressed in many tumor types, tumor stem cells, and the tumor neovasculature. Furthermore, a clinical study has demonstrated that tumor cells exhibit increased riboflavin metabolism as compared to normal cells. Moreover, riboflavin and its derivatives have been conjugated to ultrasmall iron oxide nanoparticles, polyethylene glycol polymers, dendrimers, and liposomes. These conjugates have shown a high affinity towards tumors in preclinical studies.

References:

[1] M HEMALATHA; C S D. Bio prospecting of Riboflavin producing bacteria from different riboflavin enriched food sources[J]. Bioscience Journal, 2022. DOI:10.14393/bj-v38n0a2022-62495.

[2] JACK R. FENNESSY. Benefit of high-dose oral riboflavin therapy in riboflavin transporter deficiency[J]. Journal of the Peripheral Nervous System, 2023. DOI:10.1111/jns.12587.

[3] MILITA DARGUZYTE. Riboflavin-Targeted Drug Delivery.[J]. Cancers, 2020. DOI:10.3390/cancers12020295.