Comparative Study on Two Commercial Strains of Saccharomyces cerevisiae for Optimum Ethanol Production on Industrial Scale

Two commercial strains of Saccharomyces cerevisiae, Saf-Instant (Baker's yeast) and Ethanol red (Mutant) were compared for ethanol production during hot summer season, using molasses diluted up to 6-7° Brix containing 4%-5% sugars. The yeasts were propagated in fermentation vessels to study the effects of yeast cell count and varying concentrations of Urea, DAP, inoculum size and Lactrol (Antibiotic). Continuous circulation of mash was maintained for 24 hours and after this fermenter was allowed to stay for a period of 16 hours to give time for maximum conversion of sugars into ethanol. Saccharomyces cerevisiae strain (Saf-instant) with cell concentration of 400 millions/mL at molasses sugar level of 13%–15% (pH 4.6 ± 0.2, Temp. 32°C ± 1), inoculum size of 25% (v/v), urea concentration, 150 ppm, DAP, 53.4 ppm and Lactrol,150 ppm supported maximum ethanol production (8.8%) with YP/S = 250 L ethanol per tone molasses (96.5% yield), and had significantly lower concentrations of byproducts. By selecting higher ethanol yielding yeast strain and optimizing the fermentation parameters both yield and economics of the fermentation process can be improved

Comparative study for salt stress among seed, root stock and direct regenerated violet (Viola odorata L.) seedlings in relation to growth, ion contents and enzyme activities

The experiments were carried out to evaluate the comparative study for salt stress among seed, root stock and direct regenerated violet (Viola odorata L.) seedlings. Violet seedlings propagated through tissue culture (direct regeneration) had significantly higher salicylic acid (SA) concentrations from seed and rootstock propagated plants. Random amplified polymorphic DNA (RAPD) studies prior to the salt treatments revealed that genetic similarity at the molecular level among seed, root stock and direct regenerated violet seedlings was 50.9 to 70.5%. NaCl applications (50 mol m–3) reduced plant and root lengths, plant fresh and dry weights in plants obtained through seeds and rootstock as compared to direct regenerated seedlings. Direct regenerated violet showed better plant growth significantly both in saline and non-saline conditions. Seedlings raised through direct regeneration strongly inhibited accumulation of Na+, K+, Ca2+ and Cl− and organic solute accumulations as glycinebetaine (GB) and root total soluble carbohydrates (TSC) but stimulated N and relative water contents (RWC). Direct regenerated seedlings showed an enhanced catalase (CAT), ascorbate peroxidase (APX) and guaiacol dependent peroxidase (GDP) activities as compared to seed and root stock propagated plants. It was concluded that direct regenerated plants had better performance under salt stress in relation to growth and ion accumulations as compared to seed and root stock propagated violet seedlings. This might be due to higher SA concentrations in direct regenerated seedlings which resulted from somaclonal variations or growth media applied during tissue culture technique

What molecular mechanism is adapted by plants during salt stress tolerance?

Salt stress harmfully shocks agricultural yield throughout the world affecting production whether it is for subsistence or economic outcomes. The plant response to salinity consists of numerous processes that must function in coordination to alleviate both cellular hyper-osmolarity and ion disequilibrium. Salt tolerance and yield stability are complex genetic traits that are difficult to establish in crops since salt stress may occur as a catastrophic episode, be imposed continuously or intermittently and become gradually more severe at any stage during development. Molecular biology research has provided new insight into the plant response to salinity and identified genetic determinants that effect salt tolerance. Recent confirmation that many salt tolerance determinants are ubiquitous in plants has led to the use of genetic models, like Arabidopsis thaliana, to further dissect the plant salt stress response. Since manyof the most fundamental salt tolerance determinants are those that mediate cellular ion homeostasis, this review will focus primarily on the functional essentiality of ion homeostasis mechanisms in plantsalt tolerance. The transport systems that facilitate cellular capacity to utilize Na+ for osmotic adjustment and growth and the role of the Salt-Overly-Sensitive (SOS) signal transduction pathway in the regulation of ion homeostasis and salt tolerance will be particularly emphasized. The objective of the review is to know “What molecular mechanism is adopted by plants during salt stress tolerance?” A conclusion will be presented that integrates cellular based stress signaling and ion homeostasis mechanisms into a functional paradigm for whole plants and defines biotechnology strategies for enhancing salt tolerance of crops

Isolation and characterization of a bacterial strain for aniline degradation

Aniline, a serious environmental threat and health risk to living organisms is being released into the soil and water bodies owing to its expanded use in industry. The objective of the present study was to isolate a strain from rhizospheric soil samples of wheat (Triticum aestivum L.) taken from anagricultural site near the industrial area of Faisalabad, with the capability of degrading aniline with its maximum activity. The isolated strain was identified as Staphylococcus aureus ST1 a newly reported strain for aniline degradation. The strain ST1 showed tolerance up to 2000 ppm for aniline on mineral salt media plates and its degradative ability was checked through shake flasks experiments using HPLC. The strain was capable of degrading aniline and utilizing it as a sole source of carbon andenergy. Maximum reduction of aniline concentration in medium up to 59.65% was observed after 72 h. An enhancement in biodegradation was observed using glucose as an additional growth substrate. The degradative products analyzed by HPLC were catechol, phenol and some other unknown compounds. Plasmid curing showed the involvement of plasmid encoded genes which was later followed by the isolation of plasmid DNA, which was found to be a large one of ~40 kb having restriction sites for enzymes (EcoRI, BamHI, ClaI, StuI, PstI, and HindIII) used

Optimum spacing between grooved tubes: an experimental study

An experimental study on the optimum spacing between grooved tubes is reported in this paper. Two grooved tubes having a pitch of 10 mm and 15 mm and a plain tube were considered for the heat transfer analysis. The spacing between two tubes with the same pitch was varied from 10 mm to 35 mm with a step size of 5 mm. The velocity of air flowing over the tube surfaces was changed from 0.4 m/s to 1 m/s using a blower fan. Based on Nusselt number (Nu) the optimum spacing between the tubes was decided. The optimum spacing between grooved tubes of pitch 10 mm and 15 mm was compared with that of plain tubes. From the experimental analysis, it was noticed that with an increase in air velocity (increase in Reynolds number) the tube surface temperature reduced irrespective of any tube considered. Nu increased with an increase in air velocity for all the tubes. The important conclusion drawn from the present study was that there exists a limiting spacing (optimum) between the tubes above which no change in Nu was observed. The spacing of 30 mm was found to be the optimum spacing between the tubes irrespective of its surface geometry modifications

Molecular and biochemical characterization of Xanthomonas axonopodis pv. citri pathotypes

Prevalence of citrus bacterial canker caused by Xanthomonas axonopodis pv. citri in citrus groves is the major impediment and limiting factor in successful citrus production. Severity varies among different species, varieties and prevailing climatic conditions. Despite extensive studies on the biology, epidemiology and management of this disease, there is still little known about the role of different biocontrol agents for management of this disease. Traditional management of X. axonopodis pv citri is brought about by chemicals which have become complicated through the development of chemical resistance, and as such, it is hazardous for health. It is necessary to identify the pathotypes of X. axonopodis pv. citri through biochemical and molecular characterization and to determine the role of different biocontrol agents (antibiotics and plant extracts), in order to find out a safer way for controlling citrus canker as disease severity results in defoliation, dieback, premature fruit drop and blemished fruit that consequently decrease fruit production and market value.Keywords: Citrus, bacterial canker, Xanthomona

Alleviation of salinity effects by exogenous applications of salicylic acid in pearl millet (Pennisetum glaucum (L.) R. Br.) seedlings

Experiments for the study of alleviation of salt stress effects by exogenous applications of salicylic acid (SA) in pearl millet (Pennisetum glaucum (L.) R. Br.) seedlings were conducted in soil filled earthen potshaving size 12 inches with 7 kg soil. Three treatments comprising, control (T0), 50-mol m-3 NaCl (T1) and T2 are having NaCl (50 mol m-3) + SA (50 mg l-1). Pots were arranged in completely randomized design (CRD) with 6 replicates. NaCl significantly reduced the plant and root lengths, plant fresh and dry weights. In contrast, NaCl did not show any adverse effect on plants treated with NaCl plus SA. Salicylic acidtreated pearl millet plants under NaCl salinity strongly reduced accumulations of Na+, K+, Ca2+ and Cl− and glycinebetaine (GB) and total soluble carbohydrates (TSC) as compared to NaCl treatments. Higher N and relative water contents (RWC) was noted in T2 (NaCl + SA) but it reduced in T1 (NaCl) as compared to control. It was concluded that SA could be used as a potential growth regulator to improve salt tolerance in plants.Keywords: Exogenous, salicylic acid, growth, ion contents, salt tolerance, pearl mille

Isolation and biochemical characterizations of the bacteria (Acidovorax avenae subsp. avenae) associated with red stripe disease of sugarcane

Studies on Acidovorax avenae subsp. avenae, associated with red stripe disease of sugarcane was conducted in the Department of Plant Pathology, Pir Mehr Ali Shah Arid Agriculture University Rawalpindi during 2009 to 2010, in collaboration with Shakarganj Sugar Research Institute (SSRI), Jhang, Pakistan. Red stripe of sugarcane were recently observed on promising clones of sugarcane planted in autumn 2009 at Ashaba Research Farm of SSRI. Bacteria were isolated from diseased plants. These isolates yielded off white convex colonies on potato dextrose agar (PDA) media at 29°C with 1.7 to 1.9 mm diameter and were yellow on yeast extract dextrose chalk agar (YDC) media at 27°C with 1.8 to 2.0 mm diameter. The bacteria were rod shape measuring 0.5 to 0.6 × 1.4 to 1.6 μm on PDA and 0.6 to 0.7 × 1.5 to 1.7 μm on YDC. Bacterial culture was stored at different temperature levels for 150 days. Reisolation of bacterial culture which was stored at 4°C showed best result on YDC at 27°C after 150 days, whereas it showed positive result after 120 days on PDA at 29°C. Bacteria were gram negative, citrate utilization was positive, oxidase was negative, catalase was positive and urease was negative. Morphological appearance and biochemical characterizations identified the bacteria as A. avenae subsp. Avenae. In vitro screening for the efficacy of various antibiotics to inhibit the growth of A. avenae subsp. avenae on YDC media showed that ampicillin and vancomycin were most effective. Artificial inoculation on sugarcane against red stripe disease was observed. Observations were made upto six weeks for disease development. Out of 27 varieties, 16 were found resistant, four moderately resistant, five moderately susceptible and two susceptible.Key words: Sugarcane, yeast extract dextrose chalk agar (YDC), potato dextrose agar (PDA), Acidovorax avenae subsp. avenae, biochemical characterization, antibiotics