Dep. of Soil and Water Systems, Twin Falls Research and Extension Center, Univ. of Idaho, 315 Fall Ave. East, Twin Falls, ID, 83303, USA.
Dep. of Biological Engineering, College of Engineering, Univ. of Idaho, 875 Perimeter Dr. MS 2060, Moscow, ID, 83844, USA.
J Environ Qual. 2020 Jul;49(4):1044-1053. doi: 10.1002/jeq2.20092. Epub 2020 Jun 3.
Duckweed has been recognized for its potential of producing biomass on nutrients from waste streams. Our research has shown that strains of duckweed can be successfully cultivated on anaerobically digested (AD) dairy manure under controlled levels of nitrogen (N) and phosphorus (P). The objective of this study was to explore the maximization of starch accumulation in Landoltia punctata (Mey.) Les & Crawford strain 0128 under different cultivation conditions using AD dairy manure as the nutrient source. Experimental results have shown that the most influential factors for starch accumulation in L. punctata were the nutrient concentration and the appropriate scheduling of nutrient starvation at the right growth stages. In our study, nutrient starvation for starch accumulation in L. punctata was achieved by incorporating nutrient addition of appropriately diluted AD dairy manure sequentially in a controlled manner under a constant light intensity of 3,000 lx. It was observed that a starch concentration of 30% (w/w) within the L. punctata biomass was achieved with an initial total N of 57.1 mg L and a total P of 6.7 mg L after a 30-d cultivation. Under the abovementioned cultivation conditions, the duckweed L. punctata recovered 16.3% (±4.0%) of total N and 25.9% (±6.6%) of total P from AD manure into its biomass. It is concluded that L. punctata can be successfully cultivated on nutrients from dairy manure for starch production, which would achieve well-being for dairy farmers by producing a feedstock for biofuels while treating dairy wastewater in an environmentally friendly manner.
浮萍已被公认为可以从废水中的营养物质中产生生物量。我们的研究表明，在氮（N）和磷（P）的受控水平下，浮萍的菌株可以在厌氧消化（AD）的奶牛粪便中成功培养。本研究的目的是探索利用 AD 奶牛粪便作为营养源，通过 Landoltia punctata（Mey.）Les & Crawford 菌株 0128 来实现淀粉积累的最大化。实验结果表明，影响浮萍淀粉积累的最主要因素是营养浓度和在适当的生长阶段适时进行营养饥饿处理。在我们的研究中，通过以适当稀释的 AD 奶牛粪便的养分添加物来实现浮萍中的淀粉积累的营养饥饿，以恒定的 3000 lx 光强度进行控制。观察到，在 30 天的培养后，初始总 N 为 57.1 mg/L，总 P 为 6.7 mg/L，浮萍生物质中达到 30%（w/w）的淀粉浓度。在上述培养条件下，浮萍从 AD 粪便中回收了 16.3%（±4.0%）的总 N 和 25.9%（±6.6%）的总 P 进入其生物质中。研究结论表明，浮萍可以成功地从奶牛粪便中的营养物质中进行淀粉生产，这将通过生产生物燃料的原料来为奶牛农民带来福利，同时以环保的方式处理奶牛废水。
