Aquatic macrophytes; Water hyacinth (Eichhornia crassipes) and Azolla, biomass have certain advantages over terrestrial plant biomass to use as non-edible feed for 2^nd generation bioenergy production. This is mainly due to the lower lignin content and higher productivity of aquatic macrophytes. These macrophytes do not require arable land. Present study explored on development of factorial approach based optimal pretreatment process for mild acid hydrolysis of Eichhornia crassipes and Azolla microphylla biomass for conversion to fermentable sugars. The simpler structure of aquatic plants translates to higher sugar recovery using milder pretreatment conditions compared to terrestrial plants. H₂SO₄ & HCl used in mild concentrations for acid hydrolysis experiments. Approximately, 20% of the dry biomass was recovered as fermentable sugar (mainly xylose) upon treatment with dilute sulphuric acid (0.5–1.5% v/v) or hydrochloric acid (2–4% v/v) at 100–120 °C for 30–60 min. Within this range of parameters, sugar yield followed a simple additive model, implying that a decrease in sugar yield is due to reduction of one parameter. This provides a choice between high temperature short time (HTST) and low temperature long time (LTLT) treatments. HTST requires sophisticated pressure vessels and correspondingly higher capital investment for the advantage of a higher throughput. LTLT treatments can be performed in cost economy manner using relatively simple equipment. For economic, environmental and technical reasons, acid addition should be kept to a minimum, which is possible by a choice of higher temperature and longer treatment time. Such pretreatment may be employed as the first step of a two-step pretreatment process prior to enzymatic saccharification of cellulosic fraction. The acid pre-treated hydrolysate of water hyacinth and Azolla microphylla explored for hydrogen production through dark fermentation process through employment of C₅ & C₆ sugar utilizing microbe Enterobacter cloacae DT-1 strain.

水生植物；水葫芦（凤眼兰）和满江红生物量比陆生植物生物量具有某些优势，可以用作^第二代生物能源生产的非食用饲料。这主要是由于较低的木质素含量和较高的水生植物生产力。这些大型植物不需要耕地。目前的研究探索了基于因子分解法的最佳预处理工艺的开发，该工艺对凤眼莲和小叶满江红生物质进行轻度酸水解以转化为可发酵糖。与陆生植物相比，使用较温和的预处理条件，水生植物的结构更简单，从而可以提高糖的回收率。高₂SO ₄和HCl以中等浓度用于酸水解实验。在100–120°C下用稀硫酸（0.5–1.5％v / v）或盐酸（2-4％v / v）处理后，大约有20％的干燥生物质作为可发酵糖（主要是木糖）被回收。 30-60分钟。在此参数范围内，糖产量遵循简单的累加模型，这意味着糖产量下降是由于一个参数的减少。这提供了高温短时（HTST）处理和低温长时间（LTLT）处理之间的选择。HTST需要复杂的压力容器并相应地增加资本投资，以提高产量。LTLT处理可以使用相对简单的设备以节省成本的方式进行。由于经济，环境和技术原因，应尽量减少酸的添加，这可以通过选择较高的温度和更长的处理时间来实现。这样的预处理可以在纤维素部分的酶促糖化之前用作两步预处理过程的第一步。水葫芦的酸预处理水解产物小叶满江红探索利用阴沟肠杆菌DT-1菌株利用C ₅和C ₆糖，通过黑暗发酵过程生产氢气。