A novel native bioenergy green alga can stably grow on waste molasses under variable temperature conditions

• Published in: Energy conversion and management Vol. 196; pp. 751 - 758
• Main Authors: Chen, Ming, Li, Yanxue, Li, Pengsong, Wang, Wenrui, Qi, Lisong, Li, Peipei, Li, Shizhong
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 15.09.2019; Elsevier Science Ltd
• Subjects: Adaptability; Algae; Aquatic plants; Bioenergy; Biofuels; Biomass; Carbon sources; Cell growth; Chlamydomonas reinhardtii; Chlorophyll; Lipids; Low temperature; Molasses; Morphology; Mountains; Native algae isolation; Optimization; Renewable energy; Sugar; Syrups & sweeteners; Temperature effects; Temperature resistance; Waste molasses conversion; Cell growth; Bioenergy; Waste molasses conversion; Temperature resistance; Native algae isolation
• ISSN: 0196-8904; 1879-2227
• DOI: 10.1016/j.enconman.2019.06.017

In the present work, a novel native bioenergy-producing green alga was isolated and purified from a local mountain. Photobiological H2 and lipid metabolism analyses indicated that this alga could serve as a candidate for renewable bioenergy resource. The strain was then defined as Coelastrum sp. strain XNY8011 though morphological and molecular characterization. The significant adaptability to wide range of temperatures for organic waste utilization of this strain is of great interest to the authors. When grew in 0.2% (w/v) molasses at low temperature like 15 °C, Coelastrum sp. strain XNY8011 produced 13.5 folds and 4.2 folds of cell biomass and chlorophylls respectively compared to the model strain Chlamydomonas reinhardtii CC503. Biomass and photosynthetic pigments productivities with temperature resistance strongly suggested this native isolated strain is one of the desired species to develop cost-saving biomass and bioenergy production at large scale. [Display omitted] •A novel bioenergy green alga XNY8011 was isolated from nature and identified.•XNY8011 cells exhibits considerable temperature adaptability in organic waste.•XNY8011 produced folds of cells in molasses at 15 and 20 °C as model strains did.•Sugar in waste molasses was utilized for cell growth of the strain. A novel bioenergy-producing green alga (lab ID.: XNY8011) was isolated from a local mountain in Beijing, China, and was identified as a strain belonging to the genus of Coelastrum on the basis of morphological and molecular characterization. Physiological analyses of photobiological H2 and lipid production suggested that XNY8011 could be a candidate for biofuels production. This strain could accumulate considerable biomass and produce massive chlorophylls in water diluted waste molasses. Three concentrations of molasses (0.1, 0.2 and 0.5%, w/v) were studied to optimize the cell growth and chlorophylls synthesis of XNY8011, and 0.2% was proved to be the optimum, in which XNY8011 could reach A600 of 1.55 ± 0.06 and produce 11.35 ± 0.93 μg/mL of chlorophylls. It was found that 25 °C is the most preferable temperature for the cell growth of XNY8011 in molasses. Interestingly, the strain XNY8011 exhibited significant low temperature adaptability when growing in waste molasses compared to typical bioenergy green algae. It produced 5.73 and 3.05 folds of cell densities in molasses than that Chlamydomonas reinhardtii CC503 and Chlorella vulgaris did under 20 °C, respectively, and even obtained 13.51 and 2.72 folds of cell densities under 15 °C, respectively. The dynamic analysis suggested that the sugar in waste molasses was utilized as carbon source for cell growth and biomass accumulation. The present study isolated a novel bioenergy-producing green alga from the native environment which could convert waste molasses to biomass and bioenergy with significant temperature adaptability.