Limayem Alya, Gonzalez Francisco, Micciche Andrew, Haller Edward, Nayak Bina, Mohapatra Shyam
a Department of Cell Biology, Microbiology and Molecular Biology , University of South Florida , Tampa , Florida , USA.
b Department of Integrative Biology , University of South Florida , Tampa , Florida , USA.
J Environ Sci Health B. 2016 Dec;51(12):868-872. doi: 10.1080/03601234.2016.1211912. Epub 2016 Aug 15.
Wastewater-algal biomass is a promising option to biofuel production. However, microbial contaminants constitute a substantial barrier to algal biofuel yield. A series of algal strains, Nannochloris oculata and Chlorella vulgaris samples (n = 30), were purchased from the University of Texas, and were used for both stock flask cultures and flat-panel vertical bioreactors. A number of media were used for isolation and differentiation of potential contaminants according to laboratory standards (CLSI). Conventional PCR amplification was performed followed by 16S rDNA sequencing to identify isolates at the species level. Nanotherapeutics involving a nanomicellar combination of natural chitosan and zinc oxide (CZNPs) were tested against the microbial lytic groups through Minimum Inhibitory Concentration (MIC) tests and Transmission Electronic Microscopy (TEM). Results indicated the presence of Pseudomonas spp., Bacillus pumilus/ safensis, Cellulosimicrobium cellulans, Micrococcus luteus and Staphylococcus epidermidis strains at a substantial level in the wastewater-fed algal reactors. TEM confirmed the effectiveness of CZNPs on the lytic group while the average MICs (mg/mL) detected for the strains, Pseudomonas spp, Micrococcus luteus, and Bacillus pumilus were 0.417, 3.33, and 1.458, respectively. Conclusively, CZNP antimicrobials proved to be effective as inhibitory agents against currently identified lytic microbial group, did not impact algae cells, and shows promise for in situ interventions.
废水藻类生物质是生物燃料生产的一个有前景的选择。然而，微生物污染物是藻类生物燃料产量的一个重大障碍。从德克萨斯大学购买了一系列藻类菌株，包括眼点拟微绿球藻和普通小球藻样本（n = 30），并将其用于摇瓶培养和平板垂直生物反应器。根据实验室标准（CLSI），使用多种培养基对潜在污染物进行分离和鉴别。进行常规PCR扩增，随后进行16S rDNA测序以在物种水平上鉴定分离株。通过最低抑菌浓度（MIC）试验和透射电子显微镜（TEM），对涉及天然壳聚糖和氧化锌纳米胶束组合（CZNPs）的纳米疗法进行了针对微生物裂解菌群的测试。结果表明，在以废水为原料的藻类反应器中，大量存在假单胞菌属、短小芽孢杆菌/耐盐芽孢杆菌、纤维微菌属、藤黄微球菌和表皮葡萄球菌菌株。TEM证实了CZNPs对裂解菌群的有效性，而检测到的假单胞菌属、藤黄微球菌和短小芽孢杆菌菌株的平均MIC（mg/mL）分别为0.417、3.33和1.458。总之，CZNPs抗菌剂被证明是针对目前鉴定出的裂解微生物群的有效抑制剂，不会影响藻类细胞，并显示出原位干预的前景。
