Abstract

Rapid mining activities in Sukinda mining area have generated a huge amount of toxic Cr(VI) which accumulated and persisted in the soil for decades and reduced rice plant productivity in adjoining agricultural fields. Hence, for the bioremediation of rice field soil, a Cr(VI) resistant, thermotolerant and fast-growing native green algal strain SM1 was selected, which rendered resistance to 60 ppm of Cr(VI). DPC assay, ICP-OES and Raman-Spectroscopic analysis confirmed 92.765% of Cr(VI) reduction within 48 h by SM1 under optimized condition. Moreover, Cr(VI) adsorption by the green alga was also established by FTIR and SEM-EDX analysis. The alga (SM1) was identified as Chlorella thermophila by 18S rDNA sequencing (MN855377). Its application significantly improved rice (Oryza sativa var. Lalata) seed germination, seedling growth, seed vigor index, pigment and protein content. CHNS(O) and ICP-OES analysis of the algal biomass depicted the presence of several organic and inorganic compounds, which can be utilized as bio-fertilizer for the rice seedlings. Field experiments on rice plant growth characteristics should be conducted to utilize this potent algal strain in chromium contaminated rice fields for the bio-reduction of Cr(VI) and improvement of rice crop productivity.

摘要

Sukinda 矿区的快速采矿活动产生了大量有毒的六价六价铬，这些有毒六价铬在土壤中积累并持续存在数十年，并降低了邻近农田的水稻产量。因此，对于稻田土壤的生物修复，选择了抗 Cr(VI)、耐热和快速生长的天然绿藻菌株 SM1，其对 60 ppm 的 Cr(VI) 具有抗性。DPC 测定、ICP-OES 和拉曼光谱分析证实，在优化条件下，SM1 在 48 小时内减少了 92.765% 的 Cr(VI)。此外，还通过 FTIR 和 SEM-EDX 分析确定了绿藻对 Cr(VI) 的吸附。藻类 (SM1)通过 18S rDNA 测序 (MN855377)被鉴定为嗜热小球藻。它的应用显着改善了水稻（Oryza sativa变种 Lalata) 种子萌发、幼苗生长、种子活力指数、色素和蛋白质含量。藻类生物质的 CHNS(O) 和 ICP-OES 分析表明存在几种有机和无机化合物，可用作水稻幼苗的生物肥料。应进行水稻植物生长特性的田间试验，以在受铬污染的稻田中利用这种有效的藻类菌株进行 Cr(VI) 的生物还原和提高水稻作物的生产力。