Utilization of Palm Oil Mill Effluent for Chlorella vulgaris Cultivation Medium under Mixotrophic Condition as Feedstock of Biofuel

Indonesia is largest palm oil producer in the world. Increasing of palm oil influence palm oil mill effluent (POME) production. Several researcher reported that POME is a potential medium for microalgae to grow. Microalgae cultivated in mixotrophic condition has received attention as according to higher biomass and lipid productivity to provide biofuel feedstock. The aim of this research is to study growth of Chlorella vulgaris cultured in POME medium using different organic carbon source under mixotrophic condition. Carbon source (glucose, glycerol, and acetic acid) was added in 0-1.2gr/l concentration in 40% and 100% POME. Biomass was harvested using autoflocculation method, and dry biomass was extracted using ultrasound method to obtain lipid content. Our result revealed that C. vulgaris could grow on mixotrophic condition in POME medium and produce higher biomass and lipid content rather than autotrophic condition. Concentration of organic source also influenced in growth rate and biomass production. This provides a promising process to utilize POME and produce biomass as feedstock of biofuel from microalgae. Keywords: biofuel feedstock; Chlorella vulgaris; Mixotrophic cultivation; POM

High water availability increases the negative impact of a native hemiparasite on its non-native host

Environmental factors alter the impacts of parasitic plants on their hosts. However, there have been no controlled studies on how water availability modulates stem hemiparasites' effects on hosts. A glasshouse experiment was conducted to investigate the association between the Australian native stem hemiparasite Cassytha pubescens and the introduced host Ulex europaeus under high (HW) and low (LW) water supply. Cassytha pubescens had a significant, negative effect on the total biomass of U. europaeus, which was more severe in HW than LW. Regardless of watering treatment, infection significantly decreased shoot and root biomass, nodule biomass, nodule biomass per unit root biomass, F-v/F-m, and nitrogen concentration of U. europaeus. Host spine sodium concentration significantly increased in response to infection in LW but not HW conditions. Host water potential was significantly higher in HW than in LW, which may have allowed the parasite to maintain higher stomatal conductances in HW. In support of this, the delta C-13 of the parasite was significantly lower in HW than in LW (and significantly higher than the host). C. pubescens also had significantly higher F-v/F-m and 66% higher biomass per unit host in the HW compared with the LW treatment. The data suggest that the enhanced performance of C. pubescens in HW resulted in higher parasite growth rates and thus a larger demand for resources from the host, leading to poorer host performance in HW compared with LW. C. pubescens should more negatively affect U. europaeus growth under wet conditions rather than under dry conditions in the field

Evaluation of a two-phase extraction system of carbohydrates and proteins from chlorella vulgaris utex 1803

Microalgae are a valuable source of high-value products and biofuels, however the high-energy cost required for the extraction of their metabolites has kept questioning on possible industrial upgrading. The aim of this study was to evaluate the effect of temperature, solvent/biomass, NaOH concentration and thermal pretreatment of the biomass in a 2-cycle carbohydrate and protein extraction system. Results shown that best conditions for carbohydrates extraction are achieved at a solvent concentration of 3.67 M, 55°C and a solvent/biomass ratio of 30mL/g. On the other side, the best conditions for protein were 3 M, 85°C and 45 mL/g. The efficiencies achieved under these conditions were 95% for carbohydrates and 98% for proteins. Using the best extraction conditions for each metabolite a thermal pre-treatment was performed at 25°C, 75°C and 105°C. Results indicate that highest efficiencies were achieved with dry biomass pretreated at 105°C, with values of 95% for carbohydrates and 98% for proteins

Fermentation kinetics including product and substrate inhibitions plus biomass death: a mathematical analysis

Fermentation is generally modelled by kinetic equations giving the time evolutions for biomass, substrate, and product concentrations. Although these equations can be solved analytically in simple cases if substrate/product inhibition and biomass death are included, they are typically solved numerically. We propose an analytical treatment of the kinetic equations --including cell death and an arbitrary number of inhibitions-- in which constant yield needs not be assumed. Equations are solved in phase space, i.e. the biomass concentration is written explicitly as a function of the substrate concentration.Comment: 4 pages, 4 figure

Fittonia verschaffeltii Response to Artificial Light Treatments: BIOMASS, Nutrient Concentrations and Physiological Changes

The purpose of the present study was to evaluate the effects of different light treatments on biomass, nutrient concentrations and physiological parameters of Fittonia verschaffeltii (Lem) Van Houtte. The aim was to establish a methodology to evaluate the effect of photosynthetically active radiation (PAR) emitted by lamps on biomass. The light treatments used were tube luminescent Dunn (TL-D), tube luminescent Dunn + light emitting diodes (LEDs) and Tube luminescent 5 (TL-5). At the end of the experimental period, biomass, nutritional, biochemical, and physiological parameters were assessed. A clear reduction in total plant dry weight under TL-D + LEDs at the end of the experiment was recorded. With respect to nutrient concentration in the different organs assessed, there was no clear response under the different light treatments. The growth under TL-D lamps resulted in the highest concentration of total soluble sugars and starch in leaves, whereas the highest value of indole 3-acetic acid concentration was under TL-5 lamps. Plants grown under TL-D + LEDs showed the lowest values of chlorophyll a, b and a + b. The relationship proposed between integrated use of spectral energy (IUSE) and total dry weight (TDW) showed a good correlation with an R2 value of 0.86, therefore we recommend this methodology to discern the effects of the different spectral qualities on plant biomass

Analysis of coastal upwelling and the production of a biomass

The coastal upwelling index derived from weather data is input to a set of coupled differential equations that describe the production of a biomass. The curl of the wind stress vector is discussed in the context of the physical extent of the upwelling structure. An analogy between temperature and biomass concentration in the upwelled coastal water is derived and the relationship is quantified. The use of remote satellite or airborne sensing to obtain biomass rate production coefficients is considered

Rice (Oryza sativa) response to temperature at similar vapour pressure deficit

Rice is one of the most important crops that provide food for most of the poor in the world. Rice production is highly vulnerable to increase in growing temperature and one strategy to cope is to use adapted genotypes. This study aims to determine rice physiological and growth responses to temperature at similar vapour pressure deficit to understand mechanisms to select for genotypes or traits adapted to high temperature. Two experiments in the Climatron of NIAES, Tsukuba, Japan: 35°C/22°C day/night temperature and 70% RH as high temperature compared with 32°C/22°C and 68% RH as control, and 32°C/22°C and 70% RH as control compared with 28°C/22°C and 69% RH as low temperature. The experiments used Akihikari, IR64, N22 and Takanari. Maximum photosynthetic rate, stomatal conductance and transpiration significantly increased while intercellular CO 2 concentration remained similar in N22 after 30 days of high temperature treatment. This translated to higher biomass in N22 during the early growth. Stem sucrose content in N22 was also highest in both temperatures. In the low temperature experiment, transpiration, intercellular CO 2 concentration and stomatal conductance in all the genotypes increased in the 32°C/22°C compared to those in the 28°C/22°C. However, there was no difference in the photosynthetic rate and total biomass between the temperatures. Total biomass followed similar trend as the leaf biomass. Takanari had higher total biomass in both temperatures. Stem sucrose content in Akihikari was higher in both temperatures. (Texte intégral

Biosorption of hexavalent chromium by Arthrobacter viscosus

Arthrobacter viscosus biomass was used for Cr(VI) biosorption. The effect of biomass concentration on Cr(VI) reduction and removal from aqueous solution was studied in the range of 1.2 to 5.3 g/L. The removal of Cr(VI) and total chromium increased linearly with the increase of biomass concentration. The best removal efficiencies of Cr(VI) and total chromium were reached for the highest biomass concentration, 72.2 % and 44.0 %, respectively. The increase in biomass concentration did not produce significant changes in the uptake values. The maximum uptake value, 8.2 mgCr/gbiomass, was obtained for a biomass concentration of 2.3 g/L.Fundação para a Ciência e a Tecnologia (FCT

Effects of water temperature on summer periphyton biomass in shallow lakes: a pan-European mesocosm experiment

Periphyton communities play an important role in shallow lakes and are controlled by direct forces such as temperature, light, nutrients, and invertebrate grazing, but also indirectly by planktivorous fish predation. We performed a pan-European lake mesocosm experiment on periphyton colonization covering five countries along a north/south geographical/temperature gradient (Estonia, Germany, Czech Republic, Turkey, and Greece). Periphyton biomass on artificial polypropylene strips exposed at 50 cm water depth at low and high nutrient regimes (with mean total phosphorus concentration of 20 and 65 µg L−1, respectively) was compared during mid-summer. No significant effect of nutrient loading on periphyton biomass was observed as nutrient concentrations in the mesocosms were generally above limiting values. Water temperature significantly enhanced summer periphyton biomass development. Additionally, direct and indirect top-down control of snails and fish emerged as a significant factor in periphyton biomass control