Development of Low-Cost Growing Media for Spirulina using Alternative Carbon Sources

Spirulina, a blue-green microalgae is grown commercially throughout the world due to the high protein content and non-toxic features of the algal biomass. The Zarrouk’s medium which contains Na2CO3 and NaHCO3 as the carbon sources is known to be the standard medium for Spirulina cultivation. Higher purchasing cost of the carbon sources is recognised to be a limiting factor for large-scale cultivation. Low-cost alternative sources of carbon which can replace Na2CO3 and NaHCO3 in the Zarrouk’s medium has a great economic impact on the commercial production. This study aimed at assessing the growth of Spirulina in different alternative sources of carbon under different concentrations. Table sugar, cassava flour, sweet potato flour and taro flour were used as alternative sources. The Zarrouk’s medium was substituted with different levels (25%, 50%, 75% and 100%) of the solutions prepared with the alternative carbon sources. The algae were cultured at room temperature for 16 days under illumination of 4,000 Lux. The growth was assessed as optical density (OD) using a spectrophotometer at 560 nm and then converted to dry weight (g L-1).According to the results, 100% carbon in the Zarrouk’s medium could be replaced by taro flour and 50% carbon could be replaced by cassava flour. A significantly higher dry weight (1.033 g L-1) was recorded from taro flour at 100% replacement level at the end of 16-day incubation. Therefore NaHCO3 and Na2CO3 in the Zarrouk’s medium could completely be replaced by taro flour solution which substantially reduces the cost of production as well. Cassava flour solution could also be used as an effective replacement while mixing with Zarrouk’s medium into the ratio 1:1. Table sugar and sweet potato flour are found to be poor sources of carbon to replace the NaHCO3 and Na2CO3 in the Zarrouk’s medium. The results could be further confirmed by assessing the growth of Spirulina under different supplementary levels of taro and cassava flour.Keywords: carbon sources, growing media, low-cost, Spirulina, Zarrouk’s mediu

Classification of Finger Joint Timber Based on Strength Index

At present, off-cut wood pieces are dumped by sawmills as they are considered to be wastes in the wood industry. Inadequate length of sawn timber material is also reported to be a limiting factor for fully utilization of timbers. Finger joint, a method which connects two small pieces of timber together is identified as a sound technique to minimize the wastage. As there is no classification system applicable for finger joint timber in Sri Lanka, the present study focused on developing a classification system for selected 32 timber species based on their strength properties. The relationship between the strength properties and density of selected timber species was also investigated. Strength properties of finger jointed timber species were evaluated by three-point bending and compression tests according to BS 373:1957 using Universal Testing Machine (UTM-100).Factors were identified through an analysis to determine the strength index for the selected samples. The strength index values were grouped into five strength classes as very low, low, medium, high and very high. Cluster analysis was used in grouping the species with similar strength properties. Regression analysis was performed to identify the strength index of compression parallel to grain, compression perpendicular to grain, modulus of elasticity and modulus of rupture varies on density. A significant correlation (p=0.05) between the strength index and timber density was observed.Keywords: Finger joint, timber classification, universal testing machine, strengthinde

Salacia reticulata wight: a review of botany phytochemistry and pharmacology.”

ABSTRACT Salacia reticulata is a large woody climbing shrub naturally found in Sri Lanka and Southern region of India. It is widely used in treating diabetes, a chronic disorder in metabolism of carbohydrates, proteins and fat due to absolute or relative deficiency of insulin secretion with/without varying degree of insulin resistance. The decoction of S. reticulata roots is also used in the treatment of gonorrhea, rheumatism, skin diseases, haemorrhoids, itching and swelling, asthma, thirst, amenorrhea and dysmenorrheal. Presence of mangiferin (a xanthone from the roots), kotalanol and salacinol (from the roots and stems) have been identified as the antidiabetic principles of S. reticulata. Chemical constituents such as 1,3-diketones, dulcitol and leucopelargonidin, iguesterin, epicatechin, phlobatannin and glycosidal tannins, triterpenes, and 30-hydroxy-20(30) dihydroisoiguesterin, hydroxyferruginol, lambertic acid, kotalagenin 16-acetate, 26-hydroxy-1,3-friedelanedione, maytenfolic acid have also been detected in the roots of S. reticulata. The antidiabetic property of Salacia is basically attributed to the inhibitory activity of intestinal enzymes (α-glucosidase and α-amylase). Inhibition of intestinal enzymes delays glucose absorption into the blood and suppresses postprandial hyperglycemia, resulting in improved glycemic control. Furthermore, mangiferin has been reported to inhibit aldose reductase activity delaying the onset or progression of diabetic complications. Though diabetes has now become an epidemic affecting millions of people worldwide, neither insulin nor other modern pharmaceuticals has been shown to modify the course of diabetic complications mainly due to the multifactorial basis that involves both genetic and environmental risk factors. Therefore, effort is being devoted to find new therapeutics aimed at multiple targets, which has become a new paradigm in drug discovery. In this context, the discoveries on S. reticulata have lead to increase the consumption of the species across the world and it has now become a subject of broad studies for diabetes management

Analysis of Customer Satisfaction and Prices of Finger Jointed Wood Products

Wood is the most valuable and versatile natural raw material which use to fulfill timber requirements of people. State Timber Corporation is the prioritise leader which introduced various innovative concepts and products to public on utilisation timber in sustainable manner. Finger joint (FJ) technique is one of the most sustainable, eco-friendly and economically valuable innovative concepts for Sri Lankan furniture industry. In this technology small timber pieces which removed as waste are jointed together using glued finger joint cut and make new products. By evaluating the risk and benefits of FJ technology it will be essential to do a survey on economic values in FJ furniture. The main objective of the study is to analyse the cost and price difference of the product and consumer preference between FJ furniture and normal furniture. The two furniture items were selected which were made from finger jointed wood (STC B-FJ 0019) and normal wood (STC B-132). Both items have same design, same measurements, same material used and but different type (finger joint and Normal. A predefined questionnaire was distributed among randomly selected 50 customers who visited State Timber Corporation showrooms to measure the awareness and satisfaction on FJ furniture. People have low awareness but high satisfaction about FJ products. Customers were satisfied with price and attractiveness of FJ products and were not satisfied with strength, trust, durability and availability. FJ products were cost effective and benefited for the waste reduction in factories. Due to the finishing labour cost, unit production cost of FJ of (Rs.171.91 ft2) was higher than normal (Rs.147.88 ft2). Although it shows high cost for customers the uniqueness, attractiveness and high demand of FJ products benefited on customers and increase economical background of producers too. FJ technology is good profitable business in furniture production sector of timber industry.Keywords: Finger joint cost, Risks, Benefits, State Timber Corporatio

SEED GERMINATION OF MASBEDDA (Gymnema sylvestre), A RARE MEDICINAL PLANT AS AFFECTED BY pH AND ORGANIC SOLVENTS

The use of plants in treating diseases can be traced to the remote past. However due tolack of organized and scientific cultivation, proper management and awareness of socialfactors, the number of these medicinal plants is decreasing at an alarming rate. Gymnemasylvestre is one of rare medicinal plant species, which has high demand in the market.Since, little information is available on germination dynamics of Gymnema seeds, thepresent investigation was carried out to study the effect of pH and organic solvents ongermination of Gymnema sylvestre seedsFresh seeds taken from the plant were used for the experiment. Five pH solutions (i.e.4,6,7,8 andlO) were used to moist the filter papers in petri dishes, which contained seeds.A separate experiment was carried out to study the effect of organic solvents (i.e.Ethanol, Ether, Xylene, and Acetone) on germination following same procedure withusing distilled water as a control. eRD was used in both experiments with 20 replicateseach containing lO seedsResults showed that significantly (p<0.05) higher germination of seeds (56% and 52%) atpH 4 and 6 respectively, whereas the lowest germination (36%) showed at pH 10. Thehighest germination (62%) was recorded from the seeds treated with distilled water,followed by Xylene (42%) and Ether (39%). A significantly (p<O.05) lower germinationwas showed in Acetone (10%) and Ethanol (6%). According to the findings of theexperiment it can be concluded that slightly acidic media would be the best pH for thegermination of Gymnema sylvestre seeds, whereas the organic solutions showed negativeeffects.

Effect of physiological status on rooting of Masbedda (Gymnema sylvestre) cuttings

Vegetative propagation by means of cuttings is an important method for starting new plants identicalto the parent plants. Many plants can be propagated with good results by cutting, though the successdepends upon the propagator's circumstances, the time of year, and the plant to be propagated. Thepresent study was carried out to investigate the effect of physiological stage on rooting of Gymnemasylvestre stem cuttings.Healthy, double nodded cuttings were made from the mature plant stock established at the Faculty ofAgriculture, University of Ruhuna. The cuttings taken from pre-flowering (Tl), flowering (T2) andpost-flowering (T3) stages were stuck into preformed holes in poly bags filled with moistened rootingmedium which consisted of sand, top soil and compost (1 :1: 1 by volume). They were placed in a shadehouse and watered once a day. The Completely Randomized Design (CRD) was used with tenreplicates. Assessment was done 75 days after for rooting. The percentage survival was not significantly(p ~ 0.05) different between cuttings taken from the pre-flowering (92%) and post-flowering (87%)stages. No significant (p ~ 0.05) differences also in the percentage of callused and rooted cuttingswere recorded between T I and T3. However, number of roots and length of the longest root percutting were significantly (p ~ 0.05) higher in Tl than any other. Furthermore, T2 showed the lowestfigures for all the parameters assessed, indicating that the physiological status of the stock plant at thetime the cuttings are excised is of great importance for the rooting process.

AN ASSESSMENT ON NATURAL REGENERATION OF Gymnema sylvestre, A RARE MEDICINAL PLANT

Gymnema sylvestre R.Br. belonging to family Asclepiadaceae, is naturallyfound in tropical forests of India and in some parts of Sri Lanka. This herb isbest known for its ability to abolish the taste of sugar and has been used inthe treatment of diabetes. A number of commercial herbal products are nowavailable that contain varying amounts of gymnemic acids, the componentresponsible for the action against diabetes. Though the demand for thespecies is increasing rapidly, the commercial cultivation of the species is yetto be expanded. On the other hand it is felt that the natural regeneration ofthis important herb is poor and this study was carried out in Matara Districtof Southern Sri Lanka to assess the natural regeneration of the species.An extensive survey was conducted in order to find the natural habitats andauthenticity was confirmed for the mother plants found in the area.Flowering, fruiting and other important physiological phases of the plantwere monitored and observations were made under natural conditions.Results revealed that Gymnema is propagated naturally by means of seedgermination only. Flowering commences late in the year and mature podsrelease seeds from early February each year. The low moisture content of theseeds at the time of release together with dry environmental conditions resultin very low germination and thus the natural regeneration of the species ispoor though a single mother plant produces thousands of seeds at a season.Therefore, an alternative mode of multiplication should be made available inorder to propagate and to conserve genetic stock of this useful plant

Experimental analysis and mathematical prediction of Cd(II) removal by biosorption using support vector machines and genetic algorithms

We investigated the bioremoval of Cd(II) in batch mode, using dead and living biomass of Trichoderma viride. Kinetic studies revealed three distinct stages of the biosorption process. The pseudo-second order model and the Langmuir model described well the kinetics and equilibrium of the biosorption process, with a determination coefficient, R2 > 0.99. The value of the mean free energy of adsorption, E, is less than 16 kJ/mol at 25°C, suggesting that, at low temperature, the dominant process involved in Cd(II) biosorption by dead T. viride is the chemical ion-exchange. With the temperature increasing to 4050°C, E values are above 16 kJ/mol, showing that the particle diffusion mechanism could play an important role in Cd(II) biosorption. The studies on T. viride growth in Cd(II) solutions and its bioaccumulation performance showed that the living biomass was able to bioaccumulate 100% Cd(II) from a 50 mg/L solution at pH 6.0. The influence of pH, biomass dosage, metal concentration, contact time and temperature on the bioremoval efficiency was evaluated to further assess the biosorption capability of the dead biosorbent. These complex influences were correlated by means of a modeling procedure consisting in data driven approach in which the principles of artificial intelligence were applied with the help of support vector machines (SVM), combined with genetic algorithms (GA). According to our data, the optimal working conditions for the removal of 98.91% Cd(II) by T. viride were found for an aqueous solution containing 26.11 mg/L Cd(II) as follows: pH 6.0, contact time of 3833 min, 8 g/L biosorbent, temperature 46.5°C. The complete characterization of bioremoval parameters indicates that T. viride is an excellent material to treat wastewater containing low concentrations of metal

Comparative study on bioaccumulation of lead and cadmium by the cyanobacterium Synechocystis sp. PCC 6803 under laboratory conditions

Bioremoval techniques have been employed in cleaning water bodies that suffer from detrimental effects of heavy metal pollution. In the present laboratory study, bioaccumulation of Pb2+ and Cd2+ was assessed using the unicellular cyanobacterium Synechocystis sp. PCC 6803, a model organism widely used in genetic, physiological and morphological studies. Growth was measured as cell counts and showed that Pb2+, at low exposure concentrations (0.5 and 1 µg mL–1), had a positive influence on Synechocystis sp. PCC 6803, resulting in slight growth stimulations; however, the species could not withstand long periods of exposure to both metals at higher concentrations (2, 4, 6 and 8 µg mL–1). The highest inhibitions (53.14% and 70.07% for Pb2+ and Cd2+, respectively, at 8 µg mL–1) were recorded after six days. Rapid metal removal was observed during the first two days of incubation, followed by a gradual reduction. Though the differences in accumulated amounts seemed to be narrow, the percentage of Pb2+ removed from the solution was always higher than that of Cd2+ in all the treatments. Accumulated amounts increased in a dose-dependent manner for both metals. The maximum accumulations (155.63 and 199.83 mg g–1 dry weight for Pb2+ and Cd2+, respectively) were recorded at the end of six days. The species can be considered a good accumulator of metals, with high bioconcentration factor values of 20 657 and 24 980 for Pb2+ and Cd2+, respectively