Table 4 Hydrogen production from microalgae pretreated by physical and chemical methods
From: Fermentative hydrogen production using pretreated microalgal biomass as feedstock
Treatment methods | Substrate | Substrate concentration (g/L TS) | Inoculum | Operational conditions | Hydrogen yield (mL H2/g VS) | Comments | References |
|---|---|---|---|---|---|---|---|
Milling | Scenedesmus obliquus | 10–50 | Clostridium butyricum DSM 10702 | pH = 7.0, 37 °C; batch | 28.1–35.0 | Pure culture showed better hydrogen production than mixed culture | [24] |
Milling | Scenedesmus obliquus | 10–50 | Anaerobic sludge | pH = 7.0, 37 °C; batch | 5.4–34.8 | Hydrogen production by mixed culture showed lower H2/CO2 ratio than pure culture | [24] |
Milling | Scenedesmus obliquus | 10–50 | Anaerobic sludge | pH = 7.0, 58 °C; batch | 0.7–15.3 | Higher hydrogen production was achieved at higher temperature | [24] |
Milling | Scenedesmus obliquus | 10–50 | Anaerobic sludge + Clostridium butyricum DSM 10702 | pH = 7.0, 58 °C; batch | 32.7–48.9 | Co-culture of microorganisms achieved the highest hydrogen yield | [24] |
Heat: 100 °C, 8 h | Scenedesmus sp. (lipid extracted) | 18a | Anaerobic sludge | pH = 6.3, 37 °C; batch | 35.38 | Hydrogen production from microalgae biomass was increased by over 2 times after heat treatment at 100 °C for 8 h | [16] |
Heat: 121 °C, 15 min | Scenedesmus obliquus | 2.5–50 | Enterobacter aerogenes ATCC 13048 | pH = 6.8, 30 °C; batch | 10.8–56.5 | With the increase of substrate concentration, hydrogen yield decreased while cumulative hydrogen production and hydrogen production rate increased. Better hydrogen production was obtained from wet biomass than dried microalgae | [26] |
Heat: 121 °C, 15 min | Scenedesmus obliquus | 2.5–50 | Clostridium butyricum DSM 10702 | pH = 6.8, 37 °C; batch | 94.3–113.1 | Hydrogen yield, cumulative hydrogen production and hydrogen production rate increased with the increase of substrate concentration. Better hydrogen production was obtained from wet biomass than dried microalgae | [26] |
Heat: 121 °C, 20 min | Chlorella sorokiniana | 14 | Anaerobic sludge | pH = 6.5, 60 °C; batch | 338 | Different treatment methods on hydrogen production from microalgae biomass were examined. XRD and SEM were used to examine the rupture effect on cells by different treatment methods | [26] |
Heat: 121 °C, 4 h | Scenedesmus sp. (lipid extracted) | 18a | Anaerobic sludge | pH = 6.3, 37 °C; batch | 35.58 | Increasing treating temperature from 100 to 121 °C can achieve similar hydrogen production but shorter treating time was needed | [16] |
Base: NaOH 8 g/L, 24 h | Scenedesmus sp. (lipid extracted) | 18a | Anaerobic sludge | pH = 6.3, 37 °C; batch | 16.89 | Base treatment alone showed little effect on hydrogen production from microalgae biomass | [16] |
Chemical: H2O2 2%, 12 h | Chlorella sorokiniana | 14 | Anaerobic sludge | pH = 6.5, 60 °C; batch | 63 | H2O2 showed better effect in treating microalgae biomass than sonication, but not as effective as other methods like heat and heat-acid treatment | [25] |
Sonication: 130 W, 10 min | Chlorella sorokiniana | 14 | Anaerobic sludge | pH = 6.5, 60 °C; batch | 52 | Sonication showed little effect on cell disruption, and hydrogen production from sonication treated microalgae was not obviously increased | [25] |