Effects of different sugar sources on photoheterotrophic hydrogen production by Chlorella vulgaris
摘要
Hydrogen (H2) production by microalgae represents a promising approach to renewable energy generation. In this study, the photoheterotrophic H2 production of Chlorella vulgaris was investigated using three different sugar sources: glucose, sucrose, and fructose. Cultures were grown in a 0.5 L photobioreactor under controlled light and temperature, and assessed for H₂ yield, production rate, nutrient uptake, biomass accumulation, and light conversion efficiency (LCE). Glucose yielded the highest H2 production, producing 461.56 mL H2 L−1 (48.76 mL H2 g−1 glucose), with a maximum rate of 22.62 mL H2 L−1 h−1 and an LCE of 7.09%, likely due to its high uptake and efficient metabolism. Sucrose and fructose produced lower yields of 24.36 mL H2 L−1 (29 mL H2 g−1 sucrose) and 52.2 mL H2 L−1 (17.63 mL H2 g−1 fructose), respectively, with reduced production rates (6.96 and 13.92 mL H2 L−1 h−1, respectively) and LCEs of 2.18% and 1.23%, respectively. Sugar consumption reached 9.42 g L⁻1 for glucose, 0.84 g L−1 for sucrose, and 2.96 g L−1 for fructose; in all cases, the initial sugar concentration was 10 g L−1. Glucose also stimulated higher nutrient uptake, with 1.36 g L−1 nitrate, 137.85 mg L−1 phosphate, and 55.25 mg L−1 sulfate consumed during H2 production. This study experimentally compares the effects of various sugar sources on photoheterotrophic H2 production in C. vulgaris, elucidating the role of organic carbon availability in modulating microalgal metabolism and bioH2 yield. The findings highlight that the choice of carbon source is a critical determinant of photoheterotrophic H₂ production efficiency under nutrient-replete conditions.