Abstract：
Energy is a crucial entity for the development and it has various alternative forms of energy sources. Recently, the synthesis of nanoparticles using benign biocatalyst has attracted increased attention. In this study, silver nanoparticles were synthesized and characterized using Azadirachta indica plant-derived phytochemical as the reducing agent. Biomass of the microalga Chlorella sp. cultivated in BG11 medium increased after exposure to low concentrations of up to 0.48 mg L-1 AgNPs. In addition, algal cells treated with 0.24 mg L-1 AgNPs and cultivated in BG110 medium which contained no nitrogen source showed the highest hydrogen yield of 10.8 mmol L-1, whereas the untreated cells under the same conditions showed very low hydrogen yield of 0.003 mmol L-1. The enhanced hydrogen production observed in the treated cells was consistent with an increase in hydrogenase activity. Treatment of BG110 grown cells with low concentration of green synthesized AgNPs at 0.24 mg L-1 enhanced hydrogenase activity with a 5-fold increase of enzyme activity compared to untreated BG110 grown cells. In addition, to improve photolytic water splitting efficiency for hydrogen production, cells treated with AgNPs at 0.24 mg L-1 showed highest oxygen evolution signifying improvement in photosynthesis. The silver nanoparticles synthesized using phytochemicals derived from plant enhanced both microalgal biomass and hydrogen production with an added advantage of CO2 reduction which could be achieved due to an increase in biomass. Hence, treating microalgae with nanoparticles provided a promising strategy to reduce the atmospheric carbon dioxide as well as increasing production of hydrogen as clean energy.
摘要：
能源是发展的关键实体，它有各种替代形式的能源。最近,使用良性生物催化剂合成纳米颗粒引起了越来越多的关注。在这项研究中,使用印度氮芥植物来源的植物化学物质作为还原剂合成并表征了银纳米颗粒。微藻小球藻的生物量。在BG11培养基中培养的AgNPs暴露于低浓度的0.48mgL-1后增加。此外,用0.24mgL-1AgNPs处理并在不含氮源的BG110培养基中培养的藻类细胞显示出最高的氢产量为10.8mmolL-1，而在相同条件下未经处理的细胞显示出非常低的氢产量为0.003mmolL-1。在处理的细胞中观察到的氢气产生增强与氢化酶活性的增加一致。与未处理的BG110生长细胞相比，用低浓度的绿色合成AgNPs以0.24mgL-1处理BG110生长细胞可增强氢化酶活性，酶活性增加5倍。此外,为了提高光解水分解制氢的效率，用0.24mgL-1的AgNPs处理的细胞显示出最高的氧释放，表明光合作用的改善。使用源自植物的植物化学物质合成的银纳米颗粒增强了微藻生物质和氢气的产生,具有CO2减少的附加优势,这可以由于生物质的增加而实现。因此，用纳米颗粒处理微藻提供了一种有前途的策略，可以减少大气中的二氧化碳，并增加氢气作为清洁能源的产量。
