TABLE 3.
A set of different studies presenting contribution of and proportions between hydrogen producing bacteria and lactic acid bacteria in hydrogen-producing microbial communities.
| Lp. | Object of the study | Methods | Proportions between hydrogen producing bacteria and lactic acid bacteria | References |
| 1. | Fermentation of glucose in agitated granular sludge bed bioreactors by the sludge from domestic wastewater treatment plant in a continuous system | Polymerase-chain reaction-denaturated gradient gel electrophoresis (PCR DGGE) | High efficiency of H2 production, contribution of Clostridium sp. and Streptococcus sp. was 68% and 26%, respectively, giving the ratio of HPB:LAB ≈ 2:1 | Hung et al. (2007) |
| 2. | Fermentation of cheese whey wastewater by anaerobic digester sludge in continuous system | Cloning and sequencing of the 16S rDNA gene amplified on the total DNA isolated from the microbial community | High efficiency of H2 production, Lactobacillus 50% (including 23% sequences similar to an unpublished highly efficient hydrogen-producing bacterium), Clostridium 9% and Prevotella 7%. The estimated ratio of HPB to LAB equals 39:27 ≈ 4:3 | Yang et al. (2007) |
| 3. | 20 different lab-scale bioreactors with different configurations, operation conditions, and performances. | 16S rRNA genes 454 pyrosequencing | High efficiency of H2 production. HPB:LAB ≈ 4:3, Clostridium:LAB ≈ 7:8; Medium efficiency of H2 production, HPB:LAB ≈ 1:1, Clostridium:LAB ≈ 1:2; Low efficiency of H2 production, HPB and LAB in minority, microbial communities dominated by the Veillonellaceae family | Etchebehere et al. (2016) |
| 4. | Fermentation of tequila vinasse and Nejayote (from the maize industry) by microbial community from anaerobic digester treating food waste in batch bioreactor | Illumina MiSeq 16S rRNA sequencing | High efficiency of H2 production, Lactobacillus casei, Clostridium beijerinckii, Acetobacter lovaniensis, Sporolactobacillus terrae constituted 22.0%, 20.3%, 13.4% and 13%, respectively. Clostridium:LAB ≈ 2:3, Clostridium:Lactobacillus ≈ 1:1. | García-Depraect et al. (2017) |
| 5. | Fermentation of sugarcane vinasse in continuously operating packed-bed reactor under thermophilic condition | Illumina MiSeq 16S rRNA sequencing | High efficiency of H2 production, Clostridium (16%):Lactobacillus (24%) ≈ 2:3, additionally the Thermoanaerobacterium genus was found as hydrogen producer. | Fuess et al. (2018) |
| 6. | Fermentation of cheese whey powder with lactose by microbial community dominated by Clostridium and Streptococcus in continuously operating bioreactor | Illumina MiSeq 16S rRNA sequencing | High efficiency of H2 production, Clostridium (66%):Streptococcus (28%) ≈ 2:1, Low efficiency of H2 production, Clostridium (38%):Streptococcus (60%) ≈ 2:3 | Palomo-Briones et al. (2018) |
| 7. | Fermentation of tequila vinase in batch system by consortium (PTA-124566, American Type Culture Collection) | Illumina MiSeq 16S rRNA sequencing | Optimal H2 production, HPB (68.8%):LAB (15.2%):acetate producers (9.5%) ≈ 7:1.5:1 | García-Depraect and León-Becerril (2018) |
| 8. | Cofermentation of tequila vinasse and nixtamalization wastewater by the microbial community described in García-Depraect et al. (2017) | Illumina MiSeq 16S rRNA sequencing | High efficiency of H2 production, Clostridium (50.3%):Lactobacillus (12.0%), Streptococcus (3.8%) and Sporolactobacillus (2.7%) giving the ratio HPB:LAB ≈ 5:2 | García-Depraect et al. (2019b) |
| 9. | Cofermentation of tequila vinasse and nixtamalization wastewater by the microbial community described in García-Depraect et al. (2017) | Illumina MiSeq 16S rRNA sequencing | Optimal H2 production, Clostridium (55%):Lactobacillus (10%) and Sporolactobacillus (34%), giving the ratio HPB:LAB ≈ 5:4 | Hung et al. (2007), García-Depraect et al. (2019c) |
| 10. | Fermentation of tequila vinasse by bacterial consortium (ATCC PTA-124566) in batch experiments in well-mixed reactor | Illumina MiSeq 16S rRNA sequencing | Optimal H2 production, Clostridium (31%):Lactobacillus (55%) ≈ 1:2 | Diaz-Cruces et al. (2020) |
| 11. | Fermentation of molasses by the selected microbial communities in continuously operating PBRs | Illumina MiSeq 16S rRNA sequencing Illumina NextSeq metagenome sequencing | See Table 2 HPB (Clostridium, Ruminococcus, Prevotella):LAB (Lactobacillus, Bifidobacterium, Leuconostoc, Streptococcus, Lactococcus): High efficiency of H2 production, 2:1 (PBR1) or 1:2 (PBR5) Low efficiency of H2 production, 1:4 (PBR5) or 5:1 (PBR4) Clostridium:Lactobacillus High efficiency of H2 production, 3:1 (PBR1) or 5:6 (PBR5) Low efficiency of H2 production, 1:4 (PBR5) or 10:1 (PBR4) | This study |