Biostimulation

An innovative bioprocess method, Systematic Environmental Molecular Bioremediation Technology (SEMBT) that combines bioaugmentation and biostimulation with a molecular monitoring microarray biochip, was developed as an integrated bioremediation technology to treat S-and ...

The aim of the experiment was to evaluate the use of vegetable protein hydrolysate on Adromischus cooperi and Adromischus cristatus to improve plant growth and quality. The two experimental groups in cultivation were: i) group without protein hydrolysates, irrigated with water and substrate previously fertilized; ii) group with protein hydrolysates, irrigated with water and substrate previously fertilized. The test showed a significant increase in agronomic parameters analysed in plants treated with hydrolysed vegetable proteins, both in Adromischus cooperi and Adromischus cristatus. In fact, all plants treated showed a significant increase in total leaf count, number of new leaves, vegetative and root weight, number of inflorescences and flowering time compared to the untreated control. The application of hydrolysed proteins in plant cultivation and in particular in succulents, allows higher quality standards of the product, higher resistance to biotic and abiotic stress, increased growth rate, very interesting aspects in the field of ornamental plants.

In this study, the effect of introducing different amounts of EM-Bokashi into the growing medium of Kalanchoe Blossfeldiana was evaluated (Figure 1) to determine whether this organic soil is able to improve the growth and flowering of these succulents. The five experimental groups in cultivation were: i) group without beneficial EM-Bokashi; ii) group with 5% EM-Bokashi; iii) group with 10% EM-Bokashi; iv) group with 15% EM-Bokashi; v) group with 20% EM-Bokashi. All plants treated with EM-Bokashi showed a significant increase in the agronomic parameters analysed compared to the untreated control. The results show that the addition of Bokashi to the growing medium of Kalanchoe Blossfeldiana can improve plant quality, in particular agronomic and physiological characteristics and increased nutrient and water uptake. The analytical results lead to the following conclusions: i) the addition of already 5% Bokashi to the growing medium can bring significant improvements to the cultivation of Kalanchoe Blossfeldiana; ii) significant improvements in terms of plant and root biomass will stabilise for amounts of Bokashi in excess of 10% in the substrate; iii) EM-Bokashi significantly improves plant nutrient and water uptake; iv) plants treated with Bokashi photosynthesize and have a higher chlorophyll content and are more efficient in the use of water; v) the qualitative and physiological improvement of plants is probably determined by the presence of beneficial bacteria in the Bokashi soil conditioner, which stimulate plants and increase nutrient uptake.

El arándano azul (Vaccinium corymbosum L.), es un cultivo de importancia mundial, que ha tenido relevancia los últimos años debido a su gran beneficio para la salud humana, ya que es una gran fuente de antioxidantes. En el año 2016, México ocupó el cuarto lugar con una producción de 18.031 t, de las cuales se exportaron 17.345 t con un valor comercial de 187,9 millones de dólares (Organización de las Naciones Unidas para la Alimentación y la Agricultura [FAO], 2020).
El estrés osmótico, o lo que es consecuencia del mismo el estrés hídrico y salino, es uno de los prin¬cipales factores de estrés abiótico con efecto negativo en la producción de plantas cultivadas en el mundo. El arándano se ve sumamente afectado en rendimiento cuando se desarrolla en condiciones en las que se tenga arriba de 1 dS/m de conductividad eléctrica.
La Glicina-betaína es un compuesto cuaternario del amonio, clasificado como un bioestimulante. Se ha demostrado que la GB, Protege al fotosistema II contra el fotodaño inducido por la sal (T. Chen y N. Murata, 2010). Esto de traduce en una respuesta antiestresante para las plantas, y eventualmente se logra en una mayor eficiencia en procesos como fotosintesis y producción de biomasa en condiciones de salinidad.

The paper presents the results of research on cacti such as Gymnocalycium baldianum, Gymnocalycium mihanovichii, Notocactus eugeniae and Notocactus leninghausii, aimed at improving plant growth and defense against the pathogenic fungus Fusarium sp., through the use of Gigaspora margarita inoculated in the growing medium. Objectives of the work were: i) use Gigaspora margarita to assess if the use of arbuscular mycorrhizae can lead to an increase in the growth rate of Notocactus and Gymnocalycium, plants generally slow in their growth cycle; ii) to evaluate if the use of mycorrhizae can lead to an extension of the duration of the flower, to promote pollination of bees; iii) to assess if the use of Gigaspora Margarita allows greater protection of the roots against the fungus Fusarium sp. which often affects the roots of these cacti. The two experimental groups in cultivation were: i) group without arbuscular michorriza, irrigated with water and substrate previously fertilized; group with Gigaspora Margarita, irrigated with water and substrate previously fertilized. All plants treated with Gigaspora margarita showed a significant increase in plant height and circumference, vegetative and root weight of the plants, number of new suckers, number of flowers and fruits and flower life. In addition, there was significant control of the fungus Fusarium sp. in plants in which Gigaspora margarita was inoculated into the substrate, in fact a reduced infection of the roots due to this pathogen was found. The application of mycorrhiza in the cultivation of plants can guarantee the possibility to obtain a higher quality product, a higher resistance to biotic stress, an increase in growth rate, very interesting aspects in the succulent and cactus plants sector.

En la presente investigación se ha aplicado y comparado el método de bioestimulación con el de atenuación natural sobre suelos contaminados con hidrocarburos en la zona norte del país. La atenuación natural es la degradación generada por los microorganismos del suelo sin adición de nutrientes, mientras que en la bioestimulación se le da las condiciones de aireación, humedad y nutrientes para que los microorganismos puedan tener mayor eficiencia de remoción por su
mayor actividad, así como una mayor división de los mismos.

Otro parámetro de comparación es la relación de nutrientes C:N:P que afecta también a la remoción de hidrocarburos. El principal factor de medida de remoción ha sido establecido en función al análisis de TPH (hidrocarburos totales de petróleo).

Autores: Huguez Ames, Tecsup (Perú)/ Lizardo Visitación, Rosa Altuna y Lena Téllez, UNALM (Perú)

RESUMEN: Se realizó un experimento en laboratorio para evaluar la bioestimulación de un suelo contaminado con
aceite residual automotriz mediante la aplicación de nutrimentos, en presencia de Zea mays y Sorghum
bicolor, esto se efectuó a través de la evaluación de la producción de CO2 como indicador de la actividad
microbiana. Para ello se aplicó un arreglo factorial de 2*2*2 en un diseño completamente al azar en la que
los factores corresponden a la especie vegetal (Zea mays y Sorghum bicolor), dosis de nutrimentos y de
hidrocarburo. La producción de CO2 fue más alta en los tratamientos con hidrocarburo y nutrimentos, lo
que indica la presencia de microorganismos degradadores de hidrocarburo que se vieron estimulados por
la adición de nutrimentos en el suelo, favoreciendo de esta forma la bioestimulación del suelo.
ABSTRACT: A laboratory experiment was performed with the aim to determine the biostimulation of a contaminated soil with waste motor oil through the application of nutrients, in the presence of Zea mays and Sorghum bicolor, this was performed through the evaluation of CO2 production as indicator to microbial activity. For them we applied a factorial arrangement of 2 * 2 * 2 in a completely randomized design, in which the factors correspond to the plant species (Zea mays and Sorghum bicolor), and doses of hydrocarbon and nutrients. CO2 production was higher in the hydrocarbon and nutrient treatments, indicating the presence of hydrocarbons degrading microorganisms which were stimulated by the addition of nutrients in the soil, helping at the soil biostimulation.

As the demand for liquid petroleum increases, the need
for reliable and efficient oil spill clean-up techniques is
inevitable. Bioremediation is considered one of the most
sustainable clean-up techniques but the potential has not
been fully exploited in the field because it is too slow to
meet the immediate demands of the environment. This
study reviews the challenges to managing oil spills in
terrestrial and marine environments to identify areas
that require further research. Current challenges
associated with bioremediation of spilled petroleum
include resistance of asphalthenes to biodegradation;
delay of heavy or high molar mass polycyclic aromatic
hydrocarbon (PAH) biodegradation, eutrophication
caused by biostimulation, unsustainability of bioaugmentation in the field, poor bioavailability of spilled
petroleum, inefficiency of biodegradation in anoxic
environments and failure of successful bioremediation
laboratory studies in the field. Recommendations
offered include encouraging asphalthene biodegradation
by combining heat application (80°C), biosurfactant
(thermophilic emulsifier) and bioagumentation (using a
consortium containing Bacillus lentus and Pleurotus
tuberregium as members) but as a temporary measure,
adopting the use of ‘booms and skimmers’ and ‘organic
sorbents’ for water and land clean-up, respectively.
Heavy PAHs may be rapidly degraded by applying
nutrients (biostimulation) and biosurfactants to sites that
are oleophilic microbe-rich. Oleophilic nutrients may be
the most effective strategy to reduce eutrophication in
marine environments whilst on land, slow-release nutrient application or organic-inorganic nutrient rotation may help prevent soil hardening and infertility. The use of encapsulating agents and genetically-engineered
microbes (GEMs) may increase the efficiency of bioaugmentation in the field, but temporarily, indigenous oleophilic microbes may be employed in the field. Poor bioavailability of crude oil may be eliminated by the use of biosurfactants. In terrestrial anoxic sites, bioslurping-biosparging technology could be used whilst the marine anoxic site requires more research on how to transport nutrients and biosurfactants to oleophilic anaerobes residing in the ocean beds. The involvement of both governmental and non-governmental environmental institutions in sponsoring field studies in order to improve the reliability of bioremediation research. Further studies to
test the practicability and cost of these recommendations
in the field are needed.

In this study, the ability of PGPRs to improve the growth and rooting of Portulacaria afra in pots was evaluated. Portulacaria afra is an interesting plant from a medicinal and ornamental point of view, but it shows some difficulties in the early stages of cultivation. The two experimental groups in cultivation were: i) group without beneficial microorganisms (CTRL) (peat 60% + pumice 30% + chabazite 10%), irrigated with water and substrate previously fertilized; ii) group with beneficial microorganisms (PGPR) (peat 60% + pumice 30% + chabazite 10%), irrigated with water and substrate previously fertilized, (1,5g TNC Bactorr S13 per litre of soil). The microorganisms in TNC S13 Bactorr were: Bacillus amyloliquefaciens, B. brevis, B. cirulans, B. coagulans, B. firmus, B. halodenitrificans, B. laterosporus, B. licheniformis, B. megaterium, B. mycoides, B. pasteuri, B. polymixa, B. subtilis (1.3 x 10 11 cfu/Kg). All plants treated with Plant Growth Promoting Rhizobacteria (PGPR) showed a significant increase in the agronomic parameters analysed compared to the untreated control (CTRL), both in Portulacaria afra and in Portulacaria afra variegated. The results show that microorganisms are able to improve the absorption of water and nutrients by increasing the agronomic and physiological characteristics of plants. Very interesting aspects to improve agronomic quality, especially for those who cultivate plants from particular environments and that are poorly adapted to our climates and cultivation methods.

In this study an extract of Aschophyllum nodosum was used to improve growth and flowering in plants of Rebutia heliosa and Sulcorebutia canigueralli. The two experimental groups in cultivation were: i) group without the use of Ascophyllum nodosum (CTRL), irrigated with water and fertilized every two weeks; ii) group treated with 10% Ascophyllum nodosum (AS) powder mixed with the substrate, irrigated with water and fertilized every two weeks. All plants treated with Ascophyllum nodosum showed a significant increase in the agronomic characteristics analysed. The cacti (Rebutia heliosa and Sulcorebutia canigueralli) grown in the algae treated substrate showed a significant increase in plant height, suckers number, vegetative and roots weight, plant circumference, flowers number and flower time and seed germination. Effects certainly due to an improvement in the nutritional status of the plants induced by an increase in nutrient assimilation, which manifests itself in increased stress tolerance. Positive effects can be found especially on plant species that have difficulty in germinating, rooting and flowering or as in this experiment on plants that are slow to grow or have difficulty in being grown in greenhouses and in climatic conditions different from those in which they originated.

Biostimulation is a process by which nutrients and/or oxygen are added to enhance bioremediation. This study involved the use of Klebsiella sp. in the biodegradation of crude oil, and comparing two different methods of biostimulation-addition of oxygen (hydrogen peroxide 0.03%v/v) and addition of nutrients (fertilizer: NPK 15-15-15; 30%w/w). The microcosm experiments took place for a period of seven weeks during which the heterotrophic plate count and estimation of oil and grease content were both used to monitor the progress of biodegradation of the crude oil. Heterotrophic counts ranged from 1.0 x 10 3 to 3.1 x 10 5 CFU/gram of soil while, the oil and grease content ranged between 120mg/litre and 480 mg/litre. Treatments containing hydrogen peroxide as the only enhancement recorded the highest heterotrophic counts as well as the lowest oil and grease content at the end of the seven week duration; indicating that in this study, oxygenation had a more profound effect on increasing the rate of biodegradation of crude oil as opposed to NPK fertilizer. The heterotrophic count of the samples treated with one or both of the factors was statistically significant (P< 0.05); however, on analysis of the oil and grease content of the samples treated with one or both of the factors, it was not statistically significant (P> 0.05). INTRODUCTION Bioremediation involves the use of microorganisms to remove pollutants (Atlas and Pramer, 1990). The two general approaches to bioremediation are environmental modification, such as through fertilizer application and aeration, and addition of adapted microbial hydrocarbon degraders by seeding (Atlas and Bartha, 1992).

The article presents the results of research on succulents such as Kalanchoe pinnata, Kalanchoe tubiflora and Kalanchoe gastonis-bonnieri, aimed at improving plant growth and defense against the pathogenic fungus Pythium sp., through the use of Trichoderma viride inoculated in the medium. Objectives of the work were: 1) use Trichoderma viride to assess whether the use of this endophytic fungus can increase the growth rate of Kalanchoe pinnata, Kalanchoe tubiflora and Kalanchoe gastonis-bonnieri, plants generally slow in their growth cycle; 2) evaluate if using Trichoderma viride can lead to an increase in vitamin C content in the leaves of Kalanchoe spp.; 3) assess and evaluate how the use of Trichoderma viride allows greater protection of the roots from Pithyum sp. which often affects the roots of these succulents. The two experimental groups in cultivation were: i) group without Trichoderma spp., irrigated with water and substrate previously fertilized; ii) group with Trichoderma viride, irrigated with water and substrate previously fertilized. The test showed a significant increase in agronomic parameters analyzed in plants treated with Trichoderma viride. In fact, all plants treated showed a significant increase in height and number of leaves per plant, vegetative and root weight of plants, number and weight of new shoots, total number of germinated seeds/ 100 seeds sown and a significant reduction in average germination time. In addition, plants treated with Trichoderma show an increase in leaf vitamin C content, dry mass and a reduction in plant mortality due to Pythium sp. Tricoderma can also optimize the use of fertilizers and water by facilitating the cultivation of plants in certain locations subject to biotic and abiotic stress.

ObjectiveWe tested the hypothesis that combined 660 and 890 nm LED phototherapy will promote healing of diabetic ulcers that failed to respond to other forms of treatment.We tested the hypothesis that combined 660 and 890 nm LED phototherapy will promote healing of diabetic ulcers that failed to respond to other forms of treatment.Research Design and MethodsA double-blind randomized placebo controlled design was used to study 23 diabetic leg ulcers in two groups of 14 patients. Group one ulcers were cleaned, dressed with 1% silver sulfadiazine cream and treated with “placebo” phototherapy (<1.0 J cm−2) twice per week, using a Dynatron Solaris 705® device. Group two ulcers were treated similarly but received 3 J cm−2 dose.A double-blind randomized placebo controlled design was used to study 23 diabetic leg ulcers in two groups of 14 patients. Group one ulcers were cleaned, dressed with 1% silver sulfadiazine cream and treated with “placebo” phototherapy (<1.0 J cm−2) twice per week, using a Dynatron Solaris 705® device. Group two ulcers were treated similarly but received 3 J cm−2 dose.ResultsAt each of 15, 30, 45, 60, 75, and 90 days of healing, mean ulcer granulation and healing rates were significantly higher for group two than the “placebo” group (P < 0.02). While “placebo” treated ulcers worsened during the initial 30 days, group two ulcers healed rapidly; achieving 56% more granulation and 79.2% faster healing by day 30, and maintaining similarly higher rates of granulation and healing over the “placebo” group all through. By day 90, 58.3% of group two ulcers had healed fully and 75% had achieved 90–100% healing. In contrast, only one “placebo” treated ulcer healed fully by day 90; no other ulcer attained ≥90% healing.At each of 15, 30, 45, 60, 75, and 90 days of healing, mean ulcer granulation and healing rates were significantly higher for group two than the “placebo” group (P < 0.02). While “placebo” treated ulcers worsened during the initial 30 days, group two ulcers healed rapidly; achieving 56% more granulation and 79.2% faster healing by day 30, and maintaining similarly higher rates of granulation and healing over the “placebo” group all through. By day 90, 58.3% of group two ulcers had healed fully and 75% had achieved 90–100% healing. In contrast, only one “placebo” treated ulcer healed fully by day 90; no other ulcer attained ≥90% healing.ConclusionCombined 660 and 890 nm light promotes rapid granulation and healing of diabetic ulcers that failed to respond to other forms of treatment. Lasers Surg. Med. 41:433–441, 2009. © 2009 Wiley-Liss, Inc.Combined 660 and 890 nm light promotes rapid granulation and healing of diabetic ulcers that failed to respond to other forms of treatment. Lasers Surg. Med. 41:433–441, 2009. © 2009 Wiley-Liss, Inc.

En el presente estudio se analizó el proceso de bioremediación de un suelo contaminado con aceites usados de motor (40000 mg/kg). Se utilizaron como principales tecnologías la Atenuación Natural y la Bioestimulación adicionando nutrientes derivados de fertilizantes inorgánicos (Urea y Tripolifosfato de sodio). La dosis de nutrientes semanal fue determinada con base en relaciones estequiométricas y los requerimientos fisiológicos de la diversidad biológica del suelo. Como tratamiento de control se utilizó una muestra de suelo previamente esterilizado, al cual se adicionó HCl y Benzoato de sodio como agentes inhibidores del crecimiento microbiano. Los agentes inhibidores promovieron el crecimiento de microorganismos con capacidad hidrocarbonoclasta obteniendo la mayor eficiencia de remoción del estudio (26.5% en 12 semanas) seguido del tratamiento de Atenuación Natural y Bioestimulación. El análisis de varianza (ANOVA) de las cinéticas de remoción del contaminante presente en el suelo, indica que no existe diferencia significativa entre el proceso de Atenuación Natural y de Bioestimulación considerando la eficiencia de remoción del aceite usado, crecimiento celular y tasa de respiración del suelo.  Una prueba de toxicidad aguda utilizando el microorganismo Eisenia foetida fue realizada; con base en los resultados obtenidos no se presentó mortalidad de Eisenia foetida en ningún tratamiento, excepto en el proceso de Bioestimulación, cuya mortalidad fue del 100% como consecuencia de los niveles de amonio y pH del medio.

Soil nutrient cycling in the soil-plant system of crops relies on the effects of the agronomical practices on soil conditions, especially soil microbial population mediating soil carbon transformation (either mineralization or stabilization), nitrogen cycle including soil nitrogen transformation, uptake and return from plants, and nitrogen losses, and the fate of other elements mediating these trade-offs, including phosphorous. Arbuscular mycorrhizal fungi (AMF) are widespread, soil-borne microbes living in an obligate symbiotic status with most of the land plants. Such symbiosis can bring considerable benefits to plant growth, uptake of nutrients, and soil conditions. However, such benefits are not frequently seen in the field since the agronomical practices, especially tillage and use of fungicides, impair its development, which can partly be overcome by inoculation. Also, the increase of CO2 concentration with climate change and nitrogen fertilization could negatively affect the ...

In this study, the possibility of using a biostimulant based on liquid earthworm humus to improve the growth and quality of basil plants (Ocimum basilicum L.) was evaluated. The 3 experimental groups in cultivation were: i) group without biostimulant (CTRL), irrigated with water and substrate previously fertilized; ii) group with 1% liquid earthworm humus (ON1) and fertilised substrate; iii) group with 2% liquid earthworm humus (ON2) and fertilised substrate. The test showed a significant increase in agronomic parameters and in the percentage increase in the main constituents of basil plants treated with liquid earthworm humus. The biostimulant derived from earthworm humus combines nutritional and microbial characteristics that make it a versatile product. The varied microbial component present within the biostimulant product is very important, as it can improve both the characteristics of the soil once used and determine greater control against pathogenic microorganisms in the treated areas near the plants.

ОТРИМАННЯ ЛІНІЙ РОСЛИН ТОМАТУ СТІЙКИХ ДО ПАРАЗИТИЧНОЇ НЕМАТОДИ MELOIDOGYNE INCOGNITA ШЛЯХОМ ВИКОРИСТАННЯ БІОРЕГУЛЯТОРІВ МІКРОБІОЛОГІЧНОГО ПОХОДЖЕННЯ В УМОВАХ IN VITRO
Одним з розповсюджених та найнебезпечних шкідників томатів є паразитична нематода Meloidogyne incognita.Застосування хімічних засобів контролю над розповсюдженням нематод спричиняє негативний вплив на усі грунтові сапрофітні та симбіотичні рослинам мікроорганізми. Альтернативним напрямком для вирішення цієї проблеми є створення нових ліній томату з генетично-покращеною продуктивністю та імуно-опосередкованою стійкістю до паразитичної нематоди M. incognita за допомогою використання біорегуляторів природного походження (Аверком, Аверком нова-2, Віолар та Фітовіт) в умовах in vitro. Вплив біорегуляторів на ефективність регенерації пагонів рослин томату (Lycopersicon esculentum Mill.) сорту Лагідний та на стійкість отриманих ліній рослин до паразитичної нематоди Meloidogyne incognita за фенологічними та генетичними показниками тестували у концентраціях: 10-100 мкл на 1 літр середовища МС у комплексі з фітогормонами – ІОК та Зеатин у концентрації 1 мг/л. Найбільш ефективна регенерація пагонів спостерігалась на ізольованих сегментах гіпокотилів 10-ти денних проростків томату на живильних середовищах МС, які містили фітогормони ІОК та Зеатин у концентрації 1 мг/л у комплексі з біорегуляторами, застосованих у концентраціях: 25 мкл/л Аверкома – до 65 %, 10 мкл/л Аверкома нова-2 – до 60 %, 100 мкл/л Віолара – до 70 % та 100 мкл/л Фітовіта – до 70 %. Регенеровані пагони укорінено на живильних середовищах, що містили 10-100 мкл/л біорегуляторів мікробіологічного походження. В умовах in vitro встановлено підвищення стійкості до паразитичної нематоди M. incognita рослин-регенерантів томату за фенологічним показником - зниженню ступеню ураженості нематодою поверхні рослин-регенерантів, вирощених на живильних середовищах з біорегуляторами: Аверкомом - до 26 %, Аверкомом-нова-2 - до 39 %, Віоларом – до 36 % та Фітовітом - до 45 % порівняно з контрольними рослинами, ступінь ураженості поверхні яких складала 82 %. Виявлено також позитивний вплив біорегуляторів на підвищення стійкості до паразитичної нематоди M. incognita рослин-регенерантів томату за генетичними показниками: зміненням ступеню гомології між популяціями цитоплазматичних мРНК та si/miРНК, виділених з клітин контрольних та дослідних рослин-регенерантів, вирощених на живильних середовищах з біорегуляторами: Аверком нова-2 - на 35 %, Аверком - на 29 %, Фітовітом - на 23 %, та Віоларом - на 18 % порівняно до контролю.
SUMMARY. The results of testing different concentrations of the bioregulators of microbiological origin Avercom, Avercom nova-2, Violar and Phytovit for shoots formation of tomato (L. esculentum Mill.) in vitro conditions with the perspective for obtaining new lines of tomato cells with improved adaptive and immune-protective properties against nematode M. incognita are presented.

Soil nutrient cycling in the soil-plant system of crops relies on the effects of the agronomical practices on soil conditions, especially soil microbial population mediating soil carbon transformation (either mineralization or stabilization), nitrogen cycle including soil nitrogen transformation, uptake and return from plants, and nitrogen losses, and the fate of other elements mediating these trade-offs, including phosphorous.

This review will focus on the role of reactive oxygen species in the cellular and tissue effects of low level light therapy (LLLT). Coincidentally with the increase in electron transport and in ATP, there has also been observed by intracellular fluorescent probes and electron spin resonance an increase in intracellular reactive oxygen species (ROS) such as superoxide, hydrogen peroxide, singlet oxygen and hydroxyl radical. ROS scavengers, antioxidants and ROS quenchers block many LLLT processes. It has been proposed that light between 400-500- nm may produce ROS by a photosensitization process involving flavins, while longer wavelengths may directly produce ROS from the mitochondria. Several redox-sensitive transcription factors are known such as NF-kB and AP1, that are able to initiate transcription of genes involved in protective responses to oxidative stress. It may be the case that LLLT can be pro-oxidant in the short-term, but anti-oxidant in the long-term.

RESULTS: In Case I, the average of the first-order kinetic degradation rate constants during the first degradation stage for the bioaugmentation/biostimulation treatments was 0.0195 ± 0.0056 d −1 , which was about 2.6-fold higher than that of the control batch (0.0075 d −1 ). ...

Oil-polluted sediment bioremediation depends on both physicochemical and biological parameters, but the effect of the latter cannot be evaluated without the optimization of the former. We aimed in optimizing the physicochemical parameters related to biodegradation by applying an ex-situ landfarming set-up combined with biostimulation to oil-polluted sediment, in order to determine the added effect of bioaugmentation by four allochthonous oil-degrading bacterial consortia in relation to the degradation efficiency of the indigenous community. We monitored hydrocarbon degradation, sediment ecotoxicity and hydrolytic activity, bacterial population sizes and bacterial community dynamics, characterizing the dominant taxa through time and at each treatment. We observed no significant differences in total degradation, but increased ecotoxicity between the different treatments receiving both biostimulation and bioaugmentation and the biostimulated-only control. Moreover, the added allochthon...