Microbial and functional characterization of an allochthonous consortium applied to hydrogen production from Citrus Peel Waste in batch reactor in optimized conditions

Author(s)

Camargo, Franciele Pereira ^[1] ; Sakamoto, Isabel Kimiko ^[1] ; Delforno, Tiago Palladino ^[2] ; Mariadassou, Mahendra ^{[3, 4]} ; Loux, Valentin ^{[3, 4]} ; Midoux, Cedric ^{[3, 4, 5]} ; Silveira Duarte, Iolanda Cristina ^[2] ; Silva, Edson Luiz ^[6] ; Bize, Ariane ^[5] ; Amancio Varesche, Maria Bernadete ^[1]

Affiliation

^[1] Univ Sao Paulo, Sch Engn Sao Carlos, Dept Hydraul & Sanitat, Av Trabalhador Sao Carlene 400, BR-13566590 Sao Carlos, SP - Brazil

^[2] Fed Univ Sao Carlos UFSCar, Dept Biol, Joao Leme dos Santos Highway, Km 101, BR-18052780 Sorocaba, SP - Brazil

^[3] Univ Paris Saclay, Bioinfom, INRAE, MIGALE Bioinformat Facil, F-78350 Jouy En Josas - France

^[4] Univ Paris Saclay, INRAE, MaIAGE, F-92761 Jouy En Josas - France

^[5] Univ Paris Saclay, INRAE, PRoc biOtechnol Serv Environm PROSE, F-92761 Antony - France

^[6] Fed Univ Sao Carlos UFSCar, Dept Chem Engn, Rod Washington Luiz, Km 235, SP 310, BR-13565905 Sao Carlos, SP - Brazil

• Document type: Journal article
• Source: Journal of Environmental Management; v. 291, AUG 1 2021.
• Web of Science Citations: 0

Abstract

Energy recovery from lignocellulosic waste has been studied as an alternative to the problem of inappropriate waste disposal. The present study aimed at characterizing the microbial community and the functional activity of reactors applied to H-2 production through lignocellulosic waste fermentation in optimized conditions. The latter were identified by means of Rotational Central Composite Design (RCCD), applied to optimize allochthonous inoculum concentration (2.32-5.68 gTVS/L of granular anaerobic sludge), pH (4.32-7.68) and Citrus Peel Waste (CPW) concentration (1.55-28.45 g/L). After validation, the conditions identified for optimal H2 production were 4 gSTV/L of allochthonous inoculum, 29.8 g/L of CPW (substrate) and initial pH of 8.98. In these conditions, 48.47 mmol/L of H-2 was obtained, which is 3.64 times higher than the concentration in unoptimized conditions (13.31 mmol H-2/L using 15 g/L of CPW, 2 gTVS/L of allochthonous inoculum, pH 7.0). Acetogenesis was the predominant pathway, and maximal concentrations of 3,731 mg/L of butyric acid and 3,516 mg/L of acetic acid were observed. Regarding the metataxonomic profile, Clostridium genus was dramatically favored in the optimized condition (79.78%) when compared to the allochthonous inoculum (0.43%). It was possible to identify several genes related to H-2 (i.e dehydrogenases) and volatile fatty acids (VFA) production and with cellulose degradation, especially some CAZymes from the classes Auxiliary Activities, Glycoside Hydrolases and Glycosyl Transferase. By means of differential gene expression it was observed that cellulose degradation and acetic acid production pathways were overabundant in samples from the optimized reactors, highlighting endo-beta-1,4-glucanase/cellulose, endo-beta-1,4-xylanase, beta-glucosidase, beta-mannosidase, cellulose beta-1,4-cellobiosidase, cellobiohydrolase, and others, as main the functions. (AU)

• FAPESP's process: 17/01722-0 - Biogas obtainment and other compounds of biotechnological interest from citrus/orange processing residues
• Grantee: Franciele Pereira Camargo
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 15/06246-7 - Biorefinery concept applied to biological wastewater treatment plants: environmental pollution control coupled with material and energy recovery
• Grantee: Marcelo Zaiat
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 18/26182-1 - Microbial characterization of a consortium involved in an optimized batch reactor applied to biohydrogen production from citrus peel waste as lignocellulosic substrate
• Grantee: Franciele Pereira Camargo
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate