Sustainable bioconversion of sugarcane bagasse into valorizable riboflavin by Microbacterium proteolyticum BWBTDIPO1, characterization and in-silico mechanistic pathway prediction
Aug 2026· Frontiers in Chemical Engineering· Vol 8· 0 citations· 87 references
TL;DR
Valorizable Riboflavin obtained from waste SCB can be a green alternative to chemical Riboflavin synthesis as well as bulk SCB waste management, promoting the concept of microbe-mediated waste-to-wealth conversion, thus contributing to circular bioeconomy.
Abstract
Strategic bioconversion of lignocellulosic agro-wastes like sugarcane bagasse (SCB) into high-value Riboflavin is a rarely reported phenomenon. The present study explored a Riboflavin-producing bacterial strain,
Microbacterium proteolyticum
BWBTDIPO1 (GenBank Acc no.: PQ517523), isolated from the dumping area of Kolkata, West Bengal for its caliber to utilize SCB as a source of carbon and energy for the sustainable bio-production of the valuable nutraceutical under submerged fermentation (SmF) conditions. A strong association of bacterial growth (specific growth rate of μ = 0.325 h
-1
) with production of Riboflavin (yield of 397 ± 15.8 mgL
-
1, which amounts to 19.85 ± 2.0 mg per gram of SCB after 78 h) was recorded. Yeast extract peptone mineral salt media (YPMSM) was found to be the most suitable medium for the production. UV-Vis spectrophotometry and thin-layer chromatography (TLC) with an R
f
value of 0.83 confirmed that the metabolite was Riboflavin. The biochemical assays revealed that the strain utilized SCB components, including lignin, cellulose, and hemicellulose. Further confirmation of biomass deconstruction was assessed via FTIR, XRD, and FESEM analysis, where reports ensured successful deconstruction of SCB by the bacterial isolate. To complement the experimental findings, KEGG-based
in silico
pathway analysis was performed to explore potential metabolic routes associated with lignocellulosic biomass utilization and carbon metabolism. The predicted pathways provide a hypothetical framework for understanding biomass deconstruction and require experimental validation. This is the first report of Riboflavin production from waste SCB via bacterial treatment
(M. proteolyticum)
, indicating the novel nature of the strain and the methodology employed. Valorizable Riboflavin obtained from waste SCB can be a green alternative to chemical Riboflavin synthesis as well as bulk SCB waste management, promoting the concept of microbe-mediated waste-to-wealth conversion, thus contributing to circular bioeconomy.
This study integrates microbial biotechnology, bioprocess optimization, and circular bioeconomy principles to valorize oilseed agro-industrial coproducts as low-cost inducing substrates for lipase production. Palm kernel cake (PKC), canola cake, andiroba cake, and brewer’s spent grain were evaluated as carbon sources for extracellular lipase production by the wild-type strain Trichoderma sp. LEPM-711 under submerged fermentation. Qualitative screening in olive oil/rhodamine B medium confirmed the strain’s lipolytic potential. Among the substrates tested, PKC showed the strongest induction, reaching 4.68 U mL−1, and was therefore selected for nitrogen supplementation and statistical optimization. Peptone supplementation increased lipolytic activity to 8.41 U mL−1 after 72 h. A Plackett–Burman design identified CaCl2·2H2O, CoCl2·6H2O, and peptone as significant medium components, while response surface methodology established the optimal operational conditions as pH 6.0, 106 spores mL−1, and 2% (w/v) PKC. Under these conditions, the crude enzymatic extract reached 18.31 U mL−1 at pH 7.0 and 45 °C, corresponding to an approximately 3.9-fold increase over the initial PKC fermentation. These findings support the use of Trichoderma sp. LEPM-711 and oilseed coproducts as a sustainable platform for enzyme production and residue upgrading within applied natural sciences.
Juliana dos Santos Fernandes, R. P. Nascimento, Ivaldo Itabaiana· ET Journal· 0 citations
Residual microalgal biomass generated during wastewater phytoremediation represents an underexploited resource for developing sustainable bioprocesses. This study investigated the biotechnological valorization of phytoremediation-derived Chlorella biomass through an integrated process combining α-amylase-assisted saccharification and fermentation with the non-conventional yeast Wickerhamomyces sp. UFFS-CE-3.1.2 in a stirred-tank bioreactor. Following physical pretreatment to enhance intracellular compound accessibility, fermentation was conducted for 72 h under anaerobic conditions, and temporal changes in enzymatic activities and fermentation-associated compounds were monitored by spectrophotometric assays and high-performance liquid chromatography (HPLC), respectively. The integrated process exhibited distinct temporal profiles of hydrolytic and antioxidant enzyme activities, with maximum activities of 1275.23 U/mL for catalase, 1014.59 U/mL for ascorbate peroxidase, 1291.67 U/mL for protease, and 228.75 U/mL for lipase. Amylase activity remained detectable throughout the 72 h process. Total sugars decreased from 8.88 g/L at 0 h to 0.03 g/L at 72 h. In comparison, glycerol peaked at 5.62 g/L at 18 h, and ethanol remained at approximately 1.0 g/L between 18 and 48 h. Because several enzymatic activities were already detected before yeast inoculation, the observed profiles cannot be attributed exclusively to Wickerhamomyces sp. and should instead be interpreted as characteristics of the integrated bioprocess. Overall, the results demonstrate that residual Chlorella biomass generated during wastewater phytoremediation can serve as a renewable feedstock for further biotechnological processing, supporting an extended valorization pathway within a circular bioprocessing framework.
I. Baldasso, Emanuely Fagundes da Silva, Giseli Boni Serraglio et al.· Processes· 0 citations
The elevated biomanufacturing costs, stemming from raw material expenditures and cumbersome processes, constrain the industrial application of poly(3-hydroxybutyrate) (PHB). Valorization of biowaste in an unsterile fermentation model represents a sustainable strategy. In this study, an excellent halophile was identified and utilized for converting moldy corn to synthesize PHB. The distinguished fermentation performance and comprehensive metabolic pathways of Halomonas sp. DYZ-4 were established. Subsequently, nutrient supply and physicochemical parameters were systematically tuned to strengthen PHB accumulation. The optimal biopolymer outputs in the conventional model and the open process were accordingly 6.81 and 6.83 g L–1; a straightforward production system was thus constructed. Furthermore, moldy corn pretreated with α-amylase yielded 10.72 g L–1 reducing sugar, which could serve as a novel generation feedstock for DYZ-4 proliferation. The maximum PHB concentration reached 6.83 g L–1 with a proportion of 61%, facilitating the resource conversion of waste. This study demonstrates Halomonas as a competitive non-sterilized platform to produce PHB, presenting a potential biomanufacturing scenario for the transformation of severely damaged agricultural debris.
Agro-industrial residues from livestock and sugarcane production—particularly abundant in regions such as Veracruz, Mexico, where both agro-industries co-occur in high density—constitute underutilized carbon and nitrogen streams with high potential for biotransformation within circular bioeconomy frameworks. This study aimed to evaluate whether inoculation with Lactobacillus delbrueckii subsp. bulgaricus SP96 at increasing levels (5, 10, and 15% v/v) achieves simultaneous stabilization, carbohydrate-to-lactic-acid conversion, and nutritional enrichment of a thermally pretreated bovine manure (BM)–agro-sugarcane waste (ASCW) mixture, and to describe the underlying growth kinetics using the Gompertz model. Thermal pretreatment reduced Salmonella spp. and fecal coliforms to levels compliant with NOM-004-SEMARNAT-2002 Class B biosolid standards, yielding a substrate with suitable fermentability (14.56 gL−1 carbohydrates, 0.44% total nitrogen, pH 6.52, and 90.43% volatile solids). Fermentation at 37 °C and 120 rpm for 72 h followed Gompertz kinetics (R2 = 0.92–0.97). The 15% inoculum achieved the highest conversion efficiency and product yield (lactic acid and carbohydrate consumption), whereas the 10% inoculum represented the most balanced operating condition (best kinetic fit, R2 = 0.97). However, differences in lactic acid concentration among treatments were not statistically significant (p > 0.05). The resulting biomass showed high organic matter (93.45%), increased crude protein (8.5%), a C/N ratio of 39.9, and enrichment in P2O5, MgO, Na2O, and B. These findings validate a low-cost, scalable platform for simultaneous waste stabilization and generation of value-added, protein-enriched biomass with potential application as a feed supplement and soil amendment, pending further safety and functional characterization, from agro-livestock residues.
Karla Ramírez-Frías, S. M. Pérez-Guzmán, J. M. Hernández-Martínez et al.· Fermentation· 0 citations
Local enrichment of acidic residues on the PlGH3 surface could generate a negative electrostatic potential, which enables adaptation to high-salt and alkaline environments, thereby sustaining the enzyme's catalytic activity under such extreme conditions.
Kaijuan Wu, Ke Guo, Zheng Yu et al.· Applied Biochemistry and Bio...· 0 citations
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