Microbial Valorization of Sunflower Husk for Sustainable Biohydrogen and Biomass Production

Liana Vanyan, Akerke Toleugazykyzy, Kaisar Yegizbay, Ayaulym Daniyarova, Lyudmila Zuloyan, Gayane Mikoyan, Anait Vassilian (), Anna Poladyan (), Kairat Bekbayev () and Karen Trchounian ()
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Liana Vanyan: Research Institute of Biology, Yerevan State University, 1 A. Manoogian Str., Yerevan 0025, Armenia
Akerke Toleugazykyzy: Department of Technological Equipment, Shakarim University of Semey, St. Glinka, 20A, Semey 071410, Kazakhstan
Kaisar Yegizbay: Department of Technological Equipment, Shakarim University of Semey, St. Glinka, 20A, Semey 071410, Kazakhstan
Ayaulym Daniyarova: Department of Technological Equipment, Shakarim University of Semey, St. Glinka, 20A, Semey 071410, Kazakhstan
Lyudmila Zuloyan: Microbial Biotechnologies and Biofuel Innovation Center, Yerevan State University, 1 A. Manoogian Str., Yerevan 0025, Armenia
Gayane Mikoyan: Research Institute of Biology, Yerevan State University, 1 A. Manoogian Str., Yerevan 0025, Armenia
Anait Vassilian: Research Institute of Biology, Yerevan State University, 1 A. Manoogian Str., Yerevan 0025, Armenia
Anna Poladyan: Research Institute of Biology, Yerevan State University, 1 A. Manoogian Str., Yerevan 0025, Armenia
Kairat Bekbayev: Department of Technological Equipment, Shakarim University of Semey, St. Glinka, 20A, Semey 071410, Kazakhstan
Karen Trchounian: Research Institute of Biology, Yerevan State University, 1 A. Manoogian Str., Yerevan 0025, Armenia

Energies, 2025, vol. 18, issue 14, 1-17

Abstract: Various pretreatment methods for the valorization of sunflower husks (SHs) for H 2 gas generation through fermentation by Escherichia coli were investigated. We analyzed thermal treatment (TT), acid hydrolysis (AH), and alkaline hydrolysis (AlkH) at different substrate concentrations (50 g L −1 , 75 g L −1 , 100 g L −1 , and 150 g L −1 ) and dilution levels (undiluted, 2× diluted, and 5× diluted). A concentration of 75 g L −1 SH that was acid-hydrolyzed and dissolved twice in the medium yielded optimal microbial growth, reaching 0.3 ± 0.1 g cell dry weight (CDW) L −1 biomass. The highest substrate level enabling effective fermentation was 100 g L −1 , producing 0.37 ± 0.13 (g CDW) × L −1 biomass after complete fermentation, while 150 g L −1 exhibited pronounced inhibitory effects. It is worth mentioning that the sole alkaline treatment was not optimal for growth and H 2 production. Co-fermentation with glycerol significantly enhanced both biomass formation (up to 0.42 ± 0.15 (g CDW) × L −1 )) and H 2 production. The highest H 2 yield was observed during batch growth at 50 g L −1 SH hydrolysate with 5× dilution, reaching up to 5.7 mmol H 2 (g sugar) −1 with glycerol supplementation. This study introduces a dual-waste valorization strategy that combines agricultural and biodiesel industry residues to enhance clean energy generation. The novelty lies in optimizing pretreatment and co-substrate fermentation conditions to maximize both biohydrogen yield and microbial biomass using E. coli , a widely studied and scalable host.

Keywords: sunflower husk valorization; Escherichia coli; physicochemical treatment; co-fermentation; biohydrogen production (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2025
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