Bioremediation of crude oil contaminated tea plantation soil using two Pseudomonas aeruginosa strains AS 03 and NA 108

Crude oil contamination of soil is a major concern for tea industry in Assam, India. Crude oil is a persistent organic contaminant which alters soil physical and biochemical characteristics and makes tea plants more susceptible against crude oil contamination. Therefore, two native bacterial strains designated as AS 03 and NA 108 having crude oil degradation ability was isolated from crude oil contaminated soil. Isolates were evaluated for reduction of crude oil phytotoxicity and soil bioremediation. Biochemical and 16s ribosomal ribonucleic acid (rRNA) analysis confirmed that the bacterial strains belong to Pseudomonas aeruginosa. Under in vitro evaluation, it was found that both the strain could tolerate crude oil up to 40% (v/v). However, structural changes including morphology, difference in number of colonies were found in the presence of hydrocarbon in both AS 03 and NA 108. Also, an improvement in growth of bacterized tea plants was observed compared to non-bacterized plants grown in crude oil contaminated soil. The cumulative increment in height was 5 to 42%, compared to non-bacterized plants and with significantly higher root and shoot dry biomass accumulation. Soil treatment with both AS 03 and NA 108 improved soil quality including organic carbon, conductivity, pH and degradation of total petroleum hydrocarbon (TPH) of the contaminated soil. These findings suggest that the tested bacteria can be exploited for bioremediation of crude oil contaminated soil in the geographical region of Assam.Keywords: Pseudomonas, tea plant, total petroleum hydrocarbon, crude oilAfrican Journal of Biotechnology Vol. 12(19), pp. 2600-261

Antioxidant, photosynthesis and growth characteristics of plants grown in high sulphur coalmine overburden

151-160North East region of India suffers from high sulphur coal mine overburden (OB) and plants those survive under such condition have adopted to such harsh environment. Here, we have investigated the effect of coal mine OB substrate on biochemical, physiological and growth of two shrubs Cassia (Cassia sofera L.) and Dhaincha (Sesbania rostrata L.); two tree species Gomari (Gmelina arborea L.) and Sisso (Dalbergia sisso L.); and two monocots Citronella Grass (Cymbopogon winterianus Jowitt) and Lemon Grass (Cymbopogon citratus L). The mine OB was found to be acidic (pH 2.0) with no true soil behavior, 12.5% sulphur and more than double the trace and heavy metals compared to normal control soil. Overall, high lipid peroxidation, membrane damage, peroxidase, glutathione reductase, ascorbate peroxidase, superoxide dismutase enzymes activities along with osmolyte proline and total soluble sugar was found in mine OB plants compared to control plants. While antioxidant activities were higher, nitrate reductase activity was significantly low but reduced leaf area, total shoot and root biomass. However, the responses of antioxidant activities in mine OB plants and control plants did not follow a standard pattern of higher activities in roots followed by old>young leaves or vice versa. Further, in mine OB plants, lipid peroxidation was found significantly higher for young citronella leaves. The levels of higher glutathione reductase was found in roots than the leaves except for old leaves in Gomari while ascorbate peroxidase was found in the leaves than the roots. Overall, all the species showed higher antioxidant enzyme activities, osmolyte accumulation and membrane damage possibly due to acidity and significantly higher limit of trace and heavy metals in mine OB substrate

Protease from <i>Sporosarcina </i>sp. RRLJ 1

293-296Protease was isolated from Sporosarcina RRLJ 1 which was collected from acid tea (Camellia sinensis) plantations. It showed potential for production of the enzyme for commercial purposes. The study revealed that optimum pH for growth of the organism was 6.5-7 and supplement of casein (1%) in the medium was required for production of protease. Enzyme production and enzyme activity was maximum in 72 hr old broth culture. Maximum activity of the enzyme was found at pH 6.5

Response of Java citronella (<i>Cymbopogon winterianus </i>Jowitt) to toxic heavy metal cadmium

1267-1269Cadmium at 200 mg kg-1 soil and above concentrations was fatal as growth was inhibited ultimately leading to death of Java citronella (Cymbopogon winterianus Jowitt.). The surviving plants at 50 and 100 mg kg-1 treatments also exhibited pronounced retardation of growth and biomass yield. There was considerable reduction in the level of essential oil in herbage and oil quality deteriorated. Cadmium accumulation profile showed that highest accumulation was in root, followed by stem, leaf sheath and leaf. Very high accumulation in root for higher doses appeared to be the reason for fatality