Direct Fermentative Hydrogen Production from Cellulose and Starch with Mesophilic Bacterial Consortia

ZAGRODNIK, ROMAN; SEIFERT, KRYSTYNA

doi:10.33073/pjm-2020-015

Figures & Tables

Hydrogen production and the concentration of the metabolites during dark fermentation with anaerobic sludge pretreated at 90°C. Substrates: starch (a) and cellulose (b).

Hydrogen production and the concentration of the metabolites during dark fermentation of starch with anaerobic sludge pretreated at 100°C.

Hydrogen production and the concentration of the metabolites during dark fermentation of cellulose with anaerobic sludge pretreated at 100°C (a). Medium with MgSO4 replaced by MgCl2 (b).

Cumulative hydrogen production during repeated fed-batch dark fermentation of cellulose. AS1 – anaerobic sludge 1, AS2 – anaerobic sludge 2, ES – bacteria culture enriched on starch. Feeding days for each process: AS1 – pH 6.0 (11, 13, 16, 19, 23, 27, 31, 35, 39, 43, 47); AS2 – pH 6.0 (11, 13, 15, 18); ES – pH 6.0 (19, 23, 27, 31, 35, 39, 43, 47).

Changes in metabolites concentration during repeated fed-batch dark fermentation of cellulose. Concentrations of metabolites before and after feeding are presented. Feeding days for each process: AS1 – pH 6.0 (11, 13, 16, 19, 23, 27, 31, 35, 39, 43, 47); AS2 – pH 6.0 (11, 13, 15, 18) ; ES – pH 6.0 (19, 23, 27, 31, 35, 39, 43, 47).

The main anaerobic bioreactions during hydrogen fermentation form glucose with corresponding standard Gibbs free energies_

	ΔG° [kJ]	Eq. No.
Reaction
Acetate: C₂H₁₂O₆ + 2H₂O = > 2CH₃COOH + 4H₂ + 2CO₂	−206	1
Butyrate: C₆H₁₂O₆ = > CH₃CH₂CH₂COOH + 2H₂ + 2CO₂	−254	2
Lactate: C₆H₁₂O₆ = > 2CH₃CHOHCOOH + H⁺	−225.4	3
Ethanol: C₆H₁₂O₆ = > 2CH₃CH₂OH + 2CO₂	−164.8	4
Hydrogen consuming reactions
Homoacetogenesis: 4H₂ + 2CO₂ = > CH₃COOH + 2H₂O	−104	5
Methanogenic reactions: 4H₂ + CO₂ = > CH₄ + 2H₂O	−135	6
Sulfidogenic reactions: SO₄ ^2- + 4H₂ + H⁺ = > HS^- + 4H₂O	−152.2	7
Propionate production: C₆H₁₂O₆ + 2H₂ = > 2CH₃CH₂COOH + 2H₂O	−279.4	8

Comparison of the hydrogen production processes using untreated cellulosic material at mesophilic conditions_

Inoculum	Inoculum pretreatment	Cellulosic substrate	Conc. [g/l]	Temp. [°C]	pH initial (final)	SRE [%]	Culture conditions	Main metabolites	HPR [ml/l-h]	H₂ yield [mol H₂/mol_hexose	Ref.
Sewage sludge digester	No pretreatment	Cellulose	5.0	37	5.90 (5.90)	61	Continuous	0.3	0.10	Butyrate > acetate > valerate	(Gadow et al. 2012)
Anaerobic digester sludge	70°C (30 min)	α-Cellulose	13.5^a	37	5.5 (5.1)	NR	Batch	5	0.13	Propionate > butyrate > acetate	(Gupta et al. 2014)
Clostridium lentocellum	No pretreatment	Carboxymethyl cellulose	5	37	7.0	49	Batch	50.4	5.42^d	Acetate > butyrate > ethanol	(Zhang et al. 2019)
Cow dung compost	No pretreatment	Microcrystalline cellulose	10	37	6.8 (4.2)	55	Batch	33	2.09	Acetate > butyrate > lactate = ethanol	(Ren et al. 2010)
Anaerobic digester sludge	No pretreatment	Carboxymethyl cellulose	4	30	7.0 (NR)	NR	Batch	NR	1.72^d	Butyrate > acetate > ethanol > lactate	(Ho et al. 2012)
Anaerobic digester sludge	100°C (20 min)	Microcrystalline cellulose	5	32	6.0 (6.0)	60	Repeated fed-batch	2.3	0.63–1.04	Acetate > butyrate > propionate	This study
Anaerobic digester sludge	100°C (20 min)	Microcrystalline cellulose	25	32	6.5 (5.7)	82	Batch	3.94	0.97	Acetate > ethanol	This study
Clostridum sartagoforme FZll	No pretreatment	Microcrystalline cellulose	10	35	7.0 (NR)	83.2	Batch	7.5^c	0.53	NR	(Zhang et al. 2015)
Clostridium acetobutylicum X9 + Ethanoigenens harbinense B2	No pretreatment	Microcrystalline cellulose	12	37–40	6.0 (NR)	86	Batch	NR	1.7	Ethanol > acetate > butyrate	(Bao et al. 2016)
Clostridium termitidis + Clostridium beijerinckii	No pretreatment	Cellulose	2	37	7.2	93	Batch	2.17	1.92	Acetate > ethanol >lactate	(Gomez-Flores et al. 2017)

Hydrogen and CO2 production, hydrogen yield, an average hydrogen production rate (HPR), substrate removal efficiency (SRE), and final pH in repeated batch processes from starch (S) and cellulose (C) with inoculum pretreated at 90 or 100°C_

Process	Cycle no.	Final H₂ production [l/l_medium]	Final CO₂ production [l/l_medium]	H₂ yield [mol H₂/mol_hexose]	Average HPR [ml H₂/l/h]	SRE [%]	Final pH	Carbon recovered in metabolites [%]
S – 90°C	1	0	0.478 ± 0.056	0	0	100	5.70 ± 0.12	81
S – 90°C	2	0	0.484 ± 0.032	0	12.2 ± 1.1	100	5.16 ± 0.14	74
C – 90°C	1	0	0.42 ± 0.047	0	0.2 ± 0.1	95 ± 3	5.50 ± 0.10	75
C – 90°C	2	0	0.65 ± 0.038	0	0.5 ± 0.1	94 ± 3	5.71 ± 0.07	87
S – 100°C	1	0.003 ± 0.001	0.607 ± 0.040	0.01 ± 0.001	4.4 ± 0.3	100	4.60 ± 0.11	81
	2	1.175 ± 0.115	0.917 ± 0.079	1.60 ± 0.16	21.8 ± 2.0	100	5.05 ± 0.08	58
	3	1.121 ± 0.097	0.961 ± 0.050	1.53 ± 0.13	14.9 ± 1.2	100	5.90 ± 0.05	51
	4	1.167 ± 0.111	0.775 ± 0.074	1.59 ± 0.15	24.7 ± 2.2	100	5.05 ± 0.05	52
	5	1.298 ± 0.140	0.838 ± 0.086	1.77 ± 0.19	26.0 ± 1.9	100	5.05 ± 0.04	48
	6	1.200 ± 0.098	0.771 ± 0.059	1.63 ± 0.13	15.8 ± 1.2	100	5.05 ± 0.07	46
C – 100°C	1	0.093 ± 0.006	0.549 ± 0.061	0.14 ± 0.01	0.6 ± 0.1	90 ± 2	5.30 ± 0.12	75
	2	0.314 ± 0.019	0.892 ± 0.056	0.48 ± 0.03	0.5 ± 0.1	89 ± 1	5.95 ± 0.12	62
	3	0.007 ± 0.001	0.828 ± 0.097	0.01 ± 0.001	0.5 ± 0.1	95 ± 2	5.63 ± 0.11	85
	4	0.201 ± 0.023	0.456 ± 0.035	0.33 ± 0.04	0.4 ± 0.1	84 ± 3	5.40 ± 0.07	59
	5	0.253 ± 0.028	0.415 ± 0.047	0.39 ± 0.04	0.3 ± 0.1	89 ± 4	5.52 ± 0.08	50
C – 100°C (without SO/₄ ^2-)	1	0.585 ± 0.033	0.532 ± 0.042	0.97 ± 0.05	2.3 ± 0.2	82 ± 2	5.70 ± 0.04	56
	2	0.410 ± 0.041	0.379 ± 0.028	0.71 ± 0.07	2.6 ± 0.3	79 ± 1	4.90 ± 0.05	39
	3	0.485 ± 0.026	0.323 ± 0.022	0.93 ± 0.05	1.3 ± 0.2	71 ± 3	4.95 ± 0.09	41
	4	0.135 ± 0.014	0.337 ± 0.023	0.23 ± 0.02	1.3 ± 0.2	80 ± 2	5.02 ± 0.07	54

Hydrogen yield in repeated fed-batch processes of hydrogen production from cellulose_

Inoculum	Hydrogen yield [mol H₂/mol_hexose] after
Inoculum	1 feeding cycle	2 feeding cycle	5 feeding cycle	9 feeding cycle
AS1 – pH 6.0	1.04	0.83	0.75	0.63
AS2 – pH 6.0	0.67	0.75	0.30	–
ES – pH 6.0	0.79	0.67	0.39	0.27

Direct Fermentative Hydrogen Production from Cellulose and Starch with Mesophilic Bacterial Consortia

Figures & Tables

Fig. 1.

Fig. 2.

Fig. 3.

Fig. 4.

Fig. 5.

The main anaerobic bioreactions during hydrogen fermentation form glucose with corresponding standard Gibbs free energies_

Comparison of the hydrogen production processes using untreated cellulosic material at mesophilic conditions_

Hydrogen and CO2 production, hydrogen yield, an average hydrogen production rate (HPR), substrate removal efficiency (SRE), and final pH in repeated batch processes from starch (S) and cellulose (C) with inoculum pretreated at 90 or 100°C_

Hydrogen yield in repeated fed-batch processes of hydrogen production from cellulose_

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