scholarly journals Cultivation of energy microalga Chlorella vulgaris with low–toxic sludge extract

2021 ◽  
Vol 83 (4) ◽  
pp. 818-830
Author(s):  
Xiurong Chen ◽  
Shanshan Wang ◽  
Xiaoli Sun ◽  
Quanling Lu

Abstract Chlorella vulgaris was cultivated in different proportions of activated sludge extracts, which was from the treatment of synthetic wastewater containing tetrachlorophenol. The growth period of C. vulgaris could be shortened for about 10 days when sludge extract was mixed into BG11 culture substrate, and the growth of C. vulgaris was promoted during the period of adaptation and logarithmic period. In the stable and decay period, when the proportion of sludge extract increased to 50%, cell proliferation was inhibited. There was an evident positive correlation between the total and average amount of starch polysaccharide with sludge concentration. When C. vulgaris was cultivated with pure sludge extracts, the total amount of starch and polysaccharide was up to 103 and 125 mg/L. Therefore, the low-toxic sludge extracts were more beneficial to the accumulation of carbohydrates. In the 100% sludge extracts culture medium, chlorophyll-a in C. vulgaris was accumulated to 30.2 mg/L on the 25th day. Through the analysis of algal cells' ultrastructures, it was shown that the photosynthesis was strengthened greatly with low-toxic sludge extracts. The results show that the rich heterotrophic carbon source in the sludge extract can be used as an excellent medium for Chlorella. It provides new ideas for the harmless utilization of surplus sludge as a resource. At the same time, the use of nutrients in the sludge extract to cultivate Chlorella is of great significance to low-cost algae cultivation.

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 826
Author(s):  
Runmeng Qiao ◽  
Xin Wang ◽  
Guangjiong Qin ◽  
Qi Liu ◽  
Jialei Liu ◽  
...  

White pollution caused by agricultural films has recently attracted great attention. In some areas, the content of micro plastic in the soil has reached 30 kg/ha. The most effective way to solve this problem is to replace traditional polyethylene agricultural films with degradable agricultural films. The consistency between the degradation rate and the crop growth period has become the biggest obstacle for the wide application of such novel agricultural films. In this paper, crystallinity regulation is used to adjust the functional period of degradable agricultural films. In addition, an organic nucleating agent of polyethylenimine (PEI) is selected by doping it to poly(butylene adipate-co-terephthalate) (PBAT) polymers using a double-screw extruder. The PBAT doped with 1 wt% PEI films revealed a significant increase in mechanical properties, water holding capacity, and crystallinity compared with the pure PBAT film. There was a 31.9% increase in tensile strength, a 30.5% increase in elongation at break, a 29.6% increase in tear resistance, a 30.9% decrease in water vapor permeability, and a 3.1% increase in crystallinity. Furthermore, the induction period of PBAT doped with 1 wt% PEI under photoaging (without soil) was about 160 h longer than PBAT film, and the experienced biodegradation in soil (without light) was 1 week longer than PBAT film. Experimental results exhibited that the change of degradation degree was linearly proportional to the degree of crystallinity. This study proposes a convenient, low-cost, and effective method to adjust the crystallinity and change the degradation rate.


2021 ◽  
pp. 1-7
Author(s):  
Diane Stephenson ◽  
Reham Badawy ◽  
Soania Mathur ◽  
Maria Tome ◽  
Lynn Rochester

The burden of Parkinson’s disease (PD) continues to grow at an unsustainable pace particularly given that it now represents the fastest growing brain disease. Despite seminal discoveries in genetics and pathogenesis, people living with PD oftentimes wait years to obtain an accurate diagnosis and have no way to know their own prognostic fate once they do learn they have the disease. Currently, there is no objective biomarker to measure the onset, progression, and severity of PD along the disease continuum. Without such tools, the effectiveness of any given treatment, experimental or conventional cannot be measured. Such tools are urgently needed now more than ever given the rich number of new candidate therapies in the pipeline. Over the last decade, millions of dollars have been directed to identify biomarkers to inform progression of PD typically using molecular, fluid or imaging modalities). These efforts have produced novel insights in our understanding of PD including mechanistic targets, disease subtypes and imaging biomarkers. While we have learned a lot along the way, implementation of robust disease progression biomarkers as tools for quantifying changes in disease status or severity remains elusive. Biomarkers have improved health outcomes and led to accelerated drug approvals in key areas of unmet need such as oncology. Quantitative biomarker measures such as HbA1c a standard test for the monitoring of diabetes has impacted patient care and management, both for the healthcare professionals and the patient community. Such advances accelerate opportunities for early intervention including prevention of disease in high-risk individuals. In PD, progression markers are needed at all stages of the disease in order to catalyze drug development—this allows interventions aimed to halt or slow disease progression, very early, but also facilitates symptomatic treatments at moderate stages of the disease. Recently, attention has turned to the role of digital health technologies to complement the traditional modalities as they are relatively low cost, objective and scalable. Success in this endeavor would be transformative for clinical research and therapeutic development. Consequently, significant investment has led to a number of collaborative efforts to identify and validate suitable digital biomarkers of disease progression.


2016 ◽  
Author(s):  
A. Ribeiro ◽  
C. Vilarinho ◽  
J. Araújo ◽  
J. Carvalho

The increasing of world population, industrialization and global consuming, existing market products existed in the along with diversification of raw materials, are responsible for an exponential increase of wastes. This scenario represents loss of resources and ultimately causes air, soils and water pollution. Therefore, proper waste management is currently one of the major challenges faced by modern societies. Textile industries represents, in Portugal, almost 10% of total productive transforming sector and 19% of total employments in the sector composed by almost 7.000 companies. One of the main environmental problems of textile industries is the production of significant quantities of wastes from its different processing steps. According to the Portuguese Institute of Statistics (INE) these industries produce almost 500.000 tons of wastes each year, with the textile cotton waste (TCW) being the most expressive. It was estimated that 4.000 tons of TCW are produced each year in Portugal. In this work an integrated TCW valorisation procedure was evaluated, firstly by its thermal and energetic valorisation with slow pyrolysis followed by the utilization of biochar by-product, in lead and chromium synthetic wastewater decontamination. Pyrolysis experiments were conducted in a small scale rotating pyrolysis reactor with 0.1 m3 of total capacity. Results of pyrolysis experiments showed the formation of 0,241 m3 of biogas for each kilogram of TCW. Results also demonstrated that the biogas is mostly composed by hydrogen (22%), methane (14 %), carbon monoxide (20%) and carbon dioxide (12%), which represents a total high calorific value of 12.3 MJ/Nm3. Regarding biochar, results of elemental analysis demonstrated a high percentage of carbon driving its use as low cost adsorbent. Adsorption experiments were conducted with lead and chromium synthetic wastewaters (25, 50 and 100 mg L−1) in batch vessels with controlled pH. It was evaluated the behaviour of adsorption capacity and removal rate of each metal during 120 minutes of contact time using 5, 10 and 50 g L−1 of adsorbent dosage. Results indicated high affinity of adsorbent with each tested metal with 78% of removal rate in chromium and 95% in lead experiments. This suggests that biochar from TCW pyrolysis may be appropriated to wastewaters treatment, with high contents of heavy metals and it can be an effective alternative to activated carbon.


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.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Fan Qi ◽  
Zhang Chaoqun ◽  
Yang Weijun ◽  
Wang Qingwen ◽  
Ou Rongxian

Abstract On the basis of the world’s continuing consumption of raw materials, there was an urgent need to seek sustainable resources. Lignin, the second naturally abundant biomass, accounts for 15–35% of the cell walls of terrestrial plants and is considered waste for low-cost applications such as thermal and electricity generation. The impressive characteristics of lignin, such as its high abundance, low density, biodegradability, antioxidation, antibacterial capability, and its CO2 neutrality and enhancement, render it an ideal candidate for developing new polymer/composite materials. In past decades, considerable works have been conducted to effectively utilize waste lignin as a component in polymer matrices for the production of high-performance lignin-based polymers. This chapter is intended to provide an overview of the recent advances and challenges involving lignin-based polymers utilizing lignin macromonomer and its derived monolignols. These lignin-based polymers include phenol resins, polyurethane resins, polyester resins, epoxy resins, etc. The structural characteristics and functions of lignin-based polymers are discussed in each section. In addition, we also try to divide various lignin reinforced polymer composites into different polymer matrices, which can be separated into thermoplastics, rubber, and thermosets composites. This chapter is expected to increase the interest of researchers worldwide in lignin-based polymers and develop new ideas in this field.


Author(s):  
Chen Qian ◽  
Jianjun Li ◽  
Kaiwen Sun ◽  
Chenhui Jiang ◽  
Jialiang Huang ◽  
...  

Antimony selenosulfide, Sb2(S,Se)3, has emerged as a promising light-harvesting material for its high absorption coefficient, suitable bandgap, low-toxic and low-cost constituents. However, the poor stability and high cost of widely...


2013 ◽  
Vol 4 (1) ◽  
pp. 115-125 ◽  
Author(s):  
K Siddique-e Rabbani ◽  
A Raihan Abir ◽  
AKM Bodiuzzaman

ECG equipment is vital for diagnosis of cardiac problems. However, such equipment come from the rich Western countries at a huge cost in both procurement and maintenance, and therefore cannot offer services to a large population in the Third World countries. The only solution is to design and develop such equipment in individual countries by developing local expertise. With three decades of experience, the Dhaka University group has taken a step towards developing prototypes of ECG equipment for dissemination to the healthcare service providers. This paper presents the detailed design of an PC based ECG equipment where optimized choice of components and of the design have been made keeping the cost and maintenance in view, but not sacrificing the quality, and incorporating necessary safety features to protect the patient from known hazards. Both the hardware and the software have been developed locally and are detailed in this paper. Outputs obtained from human subjects are shown which are of reasonable good quality, and have been verified using standard ECG equipment. The PC based ECG system will allow digital post processing of signals for improved diagnosis through software. Besides, this can also become part of a nationwide telemedicine system. DOI: http://dx.doi.org/10.3329/bjmp.v4i1.14701 Bangladesh Journal of Medical Physics Vol.4 No.1 2011 115-125


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