scholarly journals Autogenous Cross-Linking of Recycled Keratin from Poultry-Feather Waste to Hydrogels for Plant-Growth Media

Polymers ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 3581
Author(s):  
Markus Brenner ◽  
Oliver Weichold

The global rise in atmospheric temperature is leading to an increasing spread of semi-arid and arid regions and is accompanied by a deterioration of arable land. Polymers can help in a number of ways, but they must not be a burden to the environment. In this context, we present herein a method by which goose feathers, representative of keratin waste in general, can be transformed into hydrogels for use as a plant growth medium. The treatment of shredded feathers in Na2S solution at ambient conditions dissolves approx. 80% of the keratin within 30 min. During evaporation, the thiol groups of cysteine reoxidise to disulphide bridges. Additionally, the protein chains form β-sheets. Both act as cross-links that enables the formation of gels. The drying conditions were found to be crucial as slower evaporation affords gels with higher degrees of swelling at the cost of reduced gel yields. The cress germination test indicated the absence of toxic substances in the gel, which strongly adheres to the roots. Thereby, the plants are protected from drought stress as long as the gel still contains moisture.

2013 ◽  
Vol 85 (4) ◽  
pp. 1427-1438 ◽  
Author(s):  
MATHIAS A. CHIA ◽  
ANA T. LOMBARDI ◽  
MARIA DA GRACA G. MELAO

The need for clean and low-cost algae production demands for investigations on algal physiological response under different growth conditions. In this research, we investigated the growth, biomass production and biochemical composition of Chlorella vulgaris using semi-continuous cultures employing three growth media (LC Oligo, Chu 10 and WC media). The highest cell density was obtained in LC Oligo, while the lowest in Chu medium. Chlorophyll a, carbohydrate and protein concentrations and yield were highest in Chu and LC Oligo media. Lipid class analysis showed that hydrocarbons (HC), sterol esthers (SE), free fatty acids (FFA), aliphatic alcohols (ALC), acetone mobile polar lipids (AMPL) and phospholipids (PL) concentrations and yields were highest in the Chu medium. Triglyceride (TAG) and sterol (ST) concentrations were highest in the LC Oligo medium. The results suggested that for cost effective cultivation, LC Oligo medium is the best choice among those studied, as it saved the cost of buying vitamins and EDTA associated with the other growth media, while at the same time resulted in the best growth performance and biomass production.


2007 ◽  
Vol 55 (1) ◽  
pp. 49 ◽  
Author(s):  
B. S. Law ◽  
M. Chidel

We compared the microclimate experienced by maternity groups of eastern cave bats (Vespadelus troughtoni) in northern New South Wales between roosts in overhang caves versus a nearby maternity roost beneath the corrugated iron roof of a farm shed. The shed’s microclimate differed dramatically from that of the caves. Caves provided well-buffered microclimate conditions, which were cooler and more humid than ambient conditions during the day, but were warmer and less humid than ambient at night. Early summer temperatures remained between 20 and 25°C in the maternity caves. In contrast, the microclimate at the shed was not buffered, with conditions varying enormously over a 24-h period, being hotter than ambient during the day (mean = 30°C, maximum = 40°C in the middle of the day), and similar to ambient at night (mean = 18°C at dawn). Rather than selecting thermal stability, lactating females selected warm, but variable, diurnal temperatures in the shed, presumably to sustain lactation. Under this situation, we estimated considerable energetic savings by roosting in the shed (27–35%, assuming normothermia) compared with that for caves, and even higher savings if bats were torpid in the mornings and passively rewarmed later (60–69%). Lactating bats therefore presumably traded-off the cost of leaving juveniles behind in a cool roost at night with these energetic benefits. In late autumn bats continued to roost in the shed with day temperatures rising above 30°C, compared with unoccupied caves, which were considerably cooler at this time (~20°C). Clarification of the estimated energy savings and the possible costs in terms of milk production requires further research to measure concurrently body temperatures, roost temperature and energy expenditure, together with juvenile growth in different types of roosts.


BioResources ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. 4891-4904
Author(s):  
Selahattin Bardak ◽  
Timucin Bardak ◽  
Hüseyin Peker ◽  
Eser Sözen ◽  
Yildiz Çabuk

Wood materials have been used in many products such as furniture, stairs, windows, and doors for centuries. There are differences in methods used to adapt wood to ambient conditions. Impregnation is a widely used method of wood preservation. In terms of efficiency, it is critical to optimize the parameters for impregnation. Data mining techniques reduce most of the cost and operational challenges with accurate prediction in the wood industry. In this study, three data-mining algorithms were applied to predict bending strength in impregnated wood materials (Pinus sylvestris L. and Millettia laurentii). Models were created from real experimental data to examine the relationship between bending strength, diffusion time, vacuum duration, and wood type, based on decision trees (DT), random forest (RF), and Gaussian process (GP) algorithms. The highest bending strength was achieved with wenge (Millettia laurentii) wood in 10 bar vacuum and the diffusion condition during 25 min. The results showed that all algorithms are suitable for predicting bending strength. The goodness of fit for the testing phase was determined as 0.994, 0.986, and 0.989 in the DT, RF, and GP algorithms, respectively. Moreover, the importance of attributes was determined in the algorithms.


2018 ◽  
Vol 1 (2) ◽  
pp. 42-52
Author(s):  
Alina Stingu ◽  
Corneliu Tanase ◽  
Valentin I. Popa

Abstract The aim of this study is to evaluate the possibility of using hemp shives as natural amendments in a phytoremediation sequence. Thus, plant growth tests were conducted for rapeseed (Brassica napus) and flax (Linum usitatissimum) in vegetation pots with sandy soil. These were seeded in a cadmium artificial contaminated environment with or without hemp shives. The efficiency of hemp shives as natural amendments was evaluated after 40 days of initiating experimental model, by evaluation of plant growth and development of plants through biometric and gravimetric measurements. Also, the concentration of assimilatory pigments was determined. In order to establish bioaccumulation capacity, degree of recovery and translocation factor, it was determined the concentration of cadmium metal ions absorbed in various parts of rapeseed and flax plants. It has been found that the development of the root system is more pronounced in the presence of hemp shives both in contamination with cadmium ions and in the absence. By determining cadmium concentrations accumulate in various parts of the plant have been shown that supplementing growth media with hemp shives, improves the bioaccumulation process of cadmium ions. According to the results, the hemp shives can be used as amendments in phytoremediation process, enhancing bioaccumulation process.


PLoS ONE ◽  
2014 ◽  
Vol 9 (12) ◽  
pp. e107689 ◽  
Author(s):  
Norman B. Best ◽  
Thomas Hartwig ◽  
Joshua S. Budka ◽  
Brandon J. Bishop ◽  
Elliot Brown ◽  
...  

2016 ◽  
Vol 46 (6) ◽  
pp. 991-995 ◽  
Author(s):  
Mara Márcia Sampaio Albuquerque ◽  
Alone Lima Brito ◽  
Andressa Priscila Piancó Santos Lima ◽  
Bruno Freitas Matos Alvim ◽  
José Raniere Ferreira de Santana

ABSTRACT: The goal of the present study was to evaluate the germination, initial growth, and in vitro co-cultivation of Comanthera curralensis Moldenke, a "sempre viva" native of the Chapada Diamantina state of Bahia. Full strength (MS) and half-strength MS (MS1/2) growth media supplemented with two different sucrose concentrations (15 and 30g L-1) were tested for germination and initial plant growth. Three different plant densities were tested by in vitro culture (8, 10 and 12 plants per container). MS1/2 medium with 15g L-1 sucrose resulted in a higher percentage of germination and plant growth for the in vitro establishment of C. curralensis. The use of 12 plants per container is indicated for cost reduction in C. curralensis in vitro production.


2011 ◽  
Vol 12 (2) ◽  
pp. 159 ◽  
Author(s):  
Mauricio Camelo R. ◽  
Sulma Paola Vera M. ◽  
Ruth Rebeca Bonilla B.

<p>La dinámica poblacional de la especie humana ha llevado a que la explotación de los recursos naturales, en búsqueda de suplir las necesidades alimenticias de los miles de millones de personas que habitan el planeta. Esta necesidad ha llevado a la utilización de materiales de alta eficiencia en la agricultura, variedades vegetales resistentes a plagas y enfermedades con ciclos de producción más cortos, agroquímicos que surten las necesidades nutricionales y provean protección frente factores bióticos adversos (plagas y enfermedades). Sin embargo, estas estrategias utilizadas en la agricultura moderna han generado impactos ambientales negativos que aún no comprendemos. La contaminación de aguas freáticas, eutrofización, aumento de gases de invernadero y acumulación de sustancias toxicas en la cadena trófica, son algunos de los graves problemas que se presentan por el uso indiscriminado de agroquímicos. Como alternativa a la utilización de estas sustancias, se ha propuesto el uso de bacterias rizosféricas que tienen reconocida acción sobre el crecimiento y desarrollo vegetal (PGPR, por sus siglas en ingles). Estas bacterias son capaces de estimular el desarrollo de las plantas de manera directa e indirecta y poseen una serie de mecanismos complejos que interactúan entre sí para establecer relaciones benéficas, especialmente con las raíces de las plantas objetivo. El estudio y entendimiento de las PGPR han sido temas de gran importancia en muchas investigaciones a nivel mundial, por esta razón esta revisión tiene por objetivo hacer una revisión parcial para dar a conocer los mecanismos que poseen las rizobacterias promotoras del crecimiento vegetal en el desarrollo de las plantas, así como el papel que desempeñan en el ciclaje de nutrientes.</p><p> </p><p><strong>Mechanisms of action of plant growth promoting rhizobacteria.</strong></p><p>The population dynamics of the human race has led to the exploitation of natural resources in search of a way to meet the nutritional needs of the billions of people inhabiting the planet. This need has led to the use of high-efficiency materials in agriculture, plant varieties with shorter production cycles that are also resistant to pests and diseases, and chemicals that provide protection against biotic factors (pests and disease), additionally the nutrients required to grow plants. However, the strategies used in modern agriculture have led to negative environmental impacts that we have yet to fully understand. Groundwater contamination, eutrophication, increased greenhouse gases, and the accumulation of toxic substances in the food chain are some of the serious problems that have arisen worldwide due to the indiscriminate use of agrochemicals. As an alternative to the use of these substances, the use of rhizopheric bacteria has been proposed owing to its known action as plant growth- promoting bacteria (PGPB). These bacteria are able to stimulate plant growth directly and indirectly and have several complex mechanisms that interact with each other to establish beneficial relationships, especially with the roots of target plants. The study and understanding of PGPR have been the subjects of great importance in many studies at a global level. This review, therefore, aims to better understand the mechanisms of plant growth-promoting rhizobacteria on plant development and their role in nutrient cycling.</p>


Water ◽  
2017 ◽  
Vol 9 (7) ◽  
pp. 501 ◽  
Author(s):  
Sally Logsdon

2020 ◽  
Vol 71 (5) ◽  
pp. 1706-1722 ◽  
Author(s):  
Marieke Dubois ◽  
Dirk Inzé

Abstract Drought stress forms a major environmental constraint during the life cycle of plants, often decreasing plant yield and in extreme cases threatening survival. The molecular and physiological responses induced by drought have been the topic of extensive research during the past decades. Because soil-based approaches to studying drought responses are often challenging due to low throughput and insufficient control of the conditions, osmotic stress assays in plates were developed to mimic drought. Addition of compounds such as polyethylene glycol, mannitol, sorbitol, or NaCl to controlled growth media has become increasingly popular since it offers the advantage of accurate control of stress level and onset. These osmotic stress assays enabled the discovery of very early stress responses, occurring within seconds or minutes following osmotic stress exposure. In this review, we construct a detailed timeline of early responses to osmotic stress, with a focus on how they initiate plant growth arrest. We further discuss the specific responses triggered by different types and severities of osmotic stress. Finally, we compare short-term plant responses under osmotic stress versus in-soil drought and discuss the advantages, disadvantages, and future of these plate-based proxies for drought.


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