Alexander Perez Cordero ¹, Deimer Vitola Romero ¹, Marcelo Marquez Castillo ¹

Affiliations
1 Agricultural Bioprospection Research Group, University of Sucre, Sincelejo, CO

Abstract

Objectives: Determine the concentration and its chemical compositions of essential oils of Lippia alba and Lippia origanoides with better inhibitory activity against the mycelial growth of Phytophthora cinnamomi phytopathogen. Methods/Statistical Analysis: In this study, the in vitro antifungal activity of essential oils of fresh and dried leaves of L. Alba and L. origanoides against P. cinnamomi was evaluated. The chemical composition of all essential oils obtained from fresh and dry leaves was evaluated using the GC-MS. A factorial design was carried out, identifying as factors the concentrations and states of leaves and plant species. Findings: The essential oils impose antifungal activity against the mycelial growth of P. cinnamomi. The essential oil of L. origanoides exhibits the highest yield of 3.3% and inhibition of 97.1%, while that of L. alba yield and inhibition was the lowest with 2.79% and 68.9% respectively. Furthermore, the essential oils obtained from dried leaves showed the highest average yields and antagonistic activity. In addition, statistical differences were found between L. Alba and L. origanoides. However, all the evaluated essential oils had activity higher than 60%, which shows their importance for agricultural uses. Improvements/Applications: This research presents essential oils as an agroecological alternative to alleviate the phytosanitary problems of crops of economic importance and as an alternative to the use of agro-toxins.

Full Text

   

Deimer Vitola Romero ¹, Alexander Pérez Cordero ², Yorly Oviedo Garizado ³

Affiliations
1 Agricultural Bioprospection Research Group, Master’s Students in Environmental Sciences Sue-Caribe, University of Sucre, Sincelejo, CO
2 Agricultural Bioprospection Research Group, University of Sucre, Sincelejo, CO
3 Master’s Students in Environmental Sciences Sue-Caribe, University of Sucre, Sincelejo, CO

Abstract

Objectives: The aim was to determine the biodegradation potential of crude oil by Chlorella sp. under mixotrophic conditions, as well as the capacity of production of biomass and photosynthetic pigments. Methods / Statistical Analysis: Concentrations of 5 g/L, 10 g/L, 15 g/L and 20 g/L crude oil were evaluated for 15 days with light intensity of 2500 lux, the oil mass removed, the production of biomass and photosynthetic pigments were measured. The treatments were carried out in triplicate and expressed as the mean ± the standard error. A ANOVA and Tukey test were carried out for the significant differences. Findings: The microalga Chlorella sp. under the conditions of mixotrophic growth showed the highest average mass removal of crude oil at concentrations of 10 g/L with a percentage of 96.64% on day 15, as well as high biomass production with 0.0786 g/mL and photosynthetic pigments on day 12 with 0.575 μg/mL for carotenoids and 1,740 μg/mL for chlorophyll-a, while chlorophyll b production was higher at the same concentration but on day 15 with 1,317 μg/mL. These results show that Chlorella sp. It has the capacity to grow under different concentrations of crude oil and this is positively influenced with high biomass production and high content of photosynthetic pigments with potential for biotechnological applications. Improvements / Applications: The mixotróficos growth conditions in vitro using crude oil as the sole source of carbon stimulate the productivity of algal biomass and photosynthetic pigments.

Full Text

   

Yaneth Hernandez ¹, Alexander Perez Cordero ¹, Deimer Vitola Romero ¹

Affiliations
1 Agricultural Bioprospection Research Group, University of Sucre, Sincelejo, CO

Abstract

Objectives: This work aimed to determine the biosorption capacity of Mercury and Nickel by the microalga Chlorella sp. present in solution and immobilized in dried fruit of Luffa cylindrica. Methods/Statistical Analysis: The algal biomass was bioaugmented in photobioreactors with 4mM Agrimins for 18±1 days in constant agitation. For the immobilization of the microalga, the sponge was used as support. The mercury and nickel removal capacity was determined by making daily growth measurements at 647 nm with a UV-vis SpectroquantPharo 300 Merck spectrophotometer. With the results an ANOVA and the Tukey test (p-value≤0.05) were performed in the InfoStat software. Findings: The results obtained showed that the microalga adheres to the fibers of the scourer, with an average immobilization of 1.58g of microalga/scourer fragment of 2.5x2.8Cm at 18 days. The results showed significant statistical differences (p-value<0.05) between, microalga in solution, immobilized, Hg and Ni concentration and between the interactions of these factors. Phycoremediation is an efficient removal technique of Hg and Ni present in contaminated water, and is potentialized when algal cells are attached to substrates that provide protection. Improvements/Applications: immobilized microalgae are an efficient alternative to remove environmental contaminants, but the type of substrate that contains the biosorbent is a key factor in the success of this biotechnology.

Full Text

   

Sandra Benítez Alvis ¹, Alexander Perez Cordero ¹, Deimer Vitola Romero ¹

Affiliations
1 Agricultural Bioprospection Research Group, University of Sucre, Sincelejo, CO

Abstract

Objectives: This research was aimed at evaluating the capacity of Mercury removal and recovery using live biomass of Chlorella sp. immobilized in scourer (Luffa cylindrica). Methods/Statistical Analysis: The algal biomass was bioaugmented in photobioreactors with 4 mM Agrimins during 20 days in constant agitation. For the immobilization of the microalga, scourer fragments were used. The mercury removal and/or desorption capacity was determined during 24 h, and desorption was carried out by acid digestion. An ANOVA and the Tukey test for significant differences (p-value ≤ 0.05) were performed with the results in the InfoStat software. Findings: an average immobilization of Chlorella sp. of 1.69g of algal cells/scourer fragment after 20 days of incubation. The statistical analysis showed significant statistical differences between all removal times, presenting the highest averages at 24 h of exposure, with a Mercury removal of 98.58% and a desorption of 82.61%. Likewise, in the lowest concentrations the microalga showed greater capacity of Mercury sorption, while at the highest concentrations the desorption of said heavy metal was greater. Improvements/Applications: Chlorella in bioremediation techniques of heavy metals are positioned as a biotechnological alternative, which thanks to its high rate of removal and desorption allows the ecological disposition of the contaminant.

Full Text