Rama Chandra Mohanty

Growth pattern changes of Chlorella vulgaris and Anabaena doliolum due to toxicity of dimethoate and endosulfan

Effects of pesticides in the ecosystem do not remain restricted to target organisms but rather extend to nontarget organisms like microorganisms which play an important role in the food chain vis-a-vis biological processes such as biogeochemical cycling, production, decomposition, interaction with other organisms, etc. Agrochemicals contaminate surface waters of agricultural regions and effectively inhibit growth, pigment biomass and survival rate of freshwater phytoplankton (Lal 1984; Adhikary 1989; Mandal and Mohanty 1990: Netrawali and Gandhi 1990). However, other toxicity method such as effect on growth pattern is useful to achieve standardization. The present paper describes the effects of two pesticides, viz., dimethoate and endosulfan on the growth patterns of Chlorella vulgaris and Anabaena doliolum.

Ethanol fermentation of sugarcane molasses by Zymomonas mobilis MTCC 92 immobilized in Luffa cylindrica L. sponge discs and Ca-alginate matrices

Bio-ethanol production from cane molasses (diluted to 15 % sugar w/v) was studied using the bacterium, Zymomonas mobilis MTCC 92 entrapped in luffa (Luffa cylindrica L.) sponge discs and Ca-alginate gel beads as the immobilizing matrices. At the end of 96 h fermentation, the final ethanol concentrations were 58.7 ± 0.09 and 59.1 ± 0.08 g/l molasses with luffa and Ca-alginate entrapped Z. mobilis cells, respectively exhibiting 83.25 ± 0.03 and 84.6 ± 0.02 % sugar conversion. There was no statistical significant difference (Fischers LSD) in sugar utilization (t = 0.254, p <0.801) and ethanol production (t =-0.663, p <0.513) between the two immobilization matrices used. Further, the immobilized cells in both the matrices were physiologically active for three more cycles of operation with less than 15 % decrease in ethanol yield in the 4thcycle, which was due to some leakage of cells. In conclusion, luffa sponge was found to be equally good as Ca-alginate as a carrier material for bacterial (Z. mobilis. cell immobilization for ethanol production. Further, it has added advantages such as it is cheap, non-corrosive and has no environmental hazard.

Ethanol fermentation of mahula (Madhuca latifolia) flowers using free and immobilized bacteria Zymomonas mobilis MTCC 92

Mahula (Madhuca latifolia L.) is a deciduous tree commonly found in the tropical rain forests of Asian and Australian continent. Corolla, the edible part of its flowers, is rich in fermentable sugar (37 ± 0.23%; on dry weight basis). Batch fermentation of mahula flowers was carried out using Zymomonas mobilis MTCC 92 free cells and cells immobilized in calcium alginate matrix. The ethanol productions were 122.9 ± 0.972 and 134.6 ± 0.104 g/kg flowers on dry weight basis using free and immobilized cells, respectively, after 96 h of fermentation, which showed that cells entrapped in calcium alginate matrix yielded 8.7% more ethanol than free cells. Further, the immobilized cells were physiologically active up to three more cycles of fermentation producing 132.7 ± 0.095, 130.5 ± 0.09 and 128.7 ± 0.056 g ethanol per kg flower in first, second and third cycle, respectively.

Differences in tree species diversity and soil nutrient status in a tropical sacred forest ecosystem on Niyamgiri hill range, Eastern Ghats, India

We have quantitatively analyzed the tree species diversity with respect to soil nutrient status in three sites of a sacred forest ecosystem of Niyamgiri hill range, Eastern Ghats, India. Extensive field surveys and sampling were conducted in 3 sites of the hill range: Site 1 Pterocarpus dominated forest (PTF) (19°40′02.2″ N and 83°21′23.1″ E), Site 2 Mangifera dominated forest (MAF) (19°40′02.8″ N and 83°21′40.8″ E) and Site 3 Mixed forest (MIF) (19°36′47.1″ N and 83°21′02.7″ E). A total of 28 families, 42 genera, 46 tree species, and 286 individual trees were recorded on an area of 0.6 ha. Tree density varied between 470 and 490 individuals ha−1 and average basal area between 3.16 and 10.04 m2 ha−1. Shannon Index (H′) ranged from 2.34 to 4.53, Simpson’s Index ranged from 0.07 to 0.09, and equitability Index ranged from 0.7 to 1.34. The number of individuals was highest in the girth at breast height (GBH) class of 50–70 cm. The soil nutrient status of the three forest types was related to tree species diversity. The soil pH value of the three sites reflected the slightly acidic nature of the area. Species diversity was positively correlated with organic carbon and phosphorus and negatively with nitrogen, EC and pH. The results of the current study may be helpful to further develop a conservation plan for tree species in tropical sacred forest ecosystems.

Salt induced changes in the growth of Chlorococcum humicolo and Scenedesmus bijugatus under nutrient limited cultures

Due to climatic changes in tropics, saline water bodies are often subject to natural fluctuations of salinity through precipitation, dessication, drought conditions or anthropogenic interference. Growth and persistence of algae under these conditions require physiological tolerance and/or resistant stages in the life cycle. Salinity, which ranges from 95.9-174.7 mg/L as NaCI, is considered as an important parameter for the Indradyumna pond (485 x 396 sq ft, maximum depth 5 m) of Puri, Orissa for it is located at a distance of 1 km from the Bay of Bengal. The fluctuation of salinity level of the pond has been observed during 1988-1991 mostly due to excessive use by innumerable number of pilgrims all over the year (Dash 1992). Increased salinity favors growth of cyanobacteria because this is the only group of photoautotrophic plankton taxa requiring Na + for growth (Allen and Arnon 1955). Green algal species like halotolerant planktonic algae (Hellebust and Le Gresley 1985), Chlorella, Ankistrodesmus and Scenedesmus (Kessler 1980) have also been found to be favored by increased salinity. However, the rationale of studying salinity tolerance of algae under nutrient limited conditions seems to be more appropriate in the bioassay method because it is established that the susceptibility / resistance characteristic of an algal species to external stress is nutritionally determined (Herbert and Bradley 1989; Mohapatra and Mohanty 1992). Accordingly, it was decided to see the effects of salinity stress on two indigenous phytoplankton species viz., Chlorococcum humicolo (Nag) Rabenh. and Scenedem~us bijugatus KUtz. in culture with differential nutrient enrichment using the sterile pond water as medium.

Comparative toxicity of two organophosphorus insecticides on membrane integrity of Chlorella vulgaris. I. effect on membrane permeability

Abstract The organophosphorus insecticides dimethoate and quinalphos caused reduction in accumulation of uranine by Chlorella vulgaris Beijerinck cells with increase in their concentrations (0-500 µM L- 1 ) in growth medium. On the other hand, there was increase in the loss of metabolites and non-metabolizable compounds like 2-deoxyglucose and 2-aminoisobutyric acid (AIBA) from the treated cells during 2 hr of treatment period. But significant loss of protein from cells was observed only at concentrations ≥ 350 µM L- 1 of the insecticides. The toxic effect of quinalphos on membrane permeability was more pronounced at each selected concentration compared to that of dimethoate. With dimethoate treatment the loss of 2-deoxyglucose, AIBA and other cellular metabolites was observed at ≥ 350 µM L- 1 concentration while with quinalphos treatment such effect was reported at ≥ 10 µM L- 1 concentration. Increased permeability of the plasma membrane of intact cells is expected to be caused by the reduction in integrity of membrane lipids. The results are discussed to arrive at the conclusion on mechanism of action of insecticides on actively growing autotrophic cells.

Cultivation of freshwater microalga Scenedesmus sp. using a low-cost inorganic fertilizer for enhanced biomass and lipid yield

The potential of an inorganic fertilizer as an alternative nutrient source for the cultivation of Scenedesmus sp. IMMTCC-6 was investigated. With a preliminary study at a shake-flask scale, the microalgae cultivation was scaled up in a photobioreactor containing an inorganic fertilizer medium. Microalgae cultured in a shake flask containing 0.1 g L(-1) of urea and 1.0 g L(-1) of NPK (Nitrogen: Phosphorus: Potassium) fertilizers showed a promising result in biomass productivity. During the scale-up study in a photobioreactor the specific growth rate (μ d(-1)), biomass yield (g L(-1)), and total biomass productivity (mg L(-1) d(-1)), was found to be 0.265, 1.19 and 66.1, respectively. The lipid yield (%) as per dry cell weight (DCW) and lipid productivity (mg L(-1) d(-1)) was found to be a maximum of 28.55 and 18.87, respectively, in a stationary phase of the microalgae growth. The fatty acids methyl ester profile was proven to be desirable for biodiesel production.

Biochemistry of post-harvest spoilage of mahula (Madhuca latifolia L.) flowers: changes in total sugar, ascorbic acid, phenol and phenylalanine ammonia-lyase activity

Mahula (Madhuca latifolia L.) is a deciduous tree found in abundance in the tropical rain forests of Asian and Australian Continents. The flowers are rich in fermentable sugars (40–47%, on fresh weight basis [fwb]), which are utilised as carbohydrate source for bio-ethanol production. Biochemical alterations in mahula flowers infected by Aspergillus niger and Rhizopus oryzae were studied, and the changes in total sugar, ascorbic acid, phenol and phenylalanine ammonia-lyase (PAL) activity in infected and healthy flowers were evaluated. The results showed a decrease in all biochemical parameters except phenol and PAL activity following fungal infection. However, there was no significant difference in different biochemical parameters between the two fungal (A. niger and R. oryzae) infected samples.

Biochemical Screening of Different Types of Sweet Potato for Bioethanol Production

Today the present scenario is focused at energy production from agricultural biomass which has emerged as one of the dependable non-traditional feedstock for the production ofbioethanol. Production of this renewable fuel, especially from starchy materials such as tuber crops, holds a remarkable potential to meet the future energy. In recent years, with the increase in price of fossil fuels, the demand of biofuel production from tuber crops such as sweet potato has increased by leaps and bounds. Among different tuber crops, sweet potato (Ipomoea batatas L.) has been considered as a promising substrate for bioethanol production and has become very important to meet the future energy crisis in developing countries. In our present study, eight varieties of sweet potatoes were collected from different region of Odisha and biochemically analysed for ethanol production. Among them, the Gouri variety collected from Odisha University of Agriculture and Technology, Bhubaneswar, exhibited maximum amount of starch (293.69±2.9 gkg−1) and sugar (326.09±2.1 gkg−1) followed by Sree Krishna variety. The Gouri type also produced maximum ethanol of1 4 7.7±0.4 gkg−1 and showed ethanol yield of 90.6%. The other varieties were exhibiting low starch and sugar content (approximately 15% less) than the Gouri variety. As the Gouri variety was more potent for starch and sugar synthesis, so this variety can be utilised for enhanced bioethanol production.