Analytical evaluation of different carbon sources and growth stimulators on the biomass and lipid production of Chlorella vulgaris – Implications for biofuels

The key challenges in lipid production from marine microalgae include the selection of appropriate strain, optimization of the culture conditions and enhancement of biolipid yield. This study is aimed at evaluating the optimal harvest time and effect of chlorella growth factor (CGF) extract, carbon sources and phytohormones on the biomass and lipid production in Chlorella vulgaris. CGF, extracted using hot water from Chlorella has been reported to possess various medicinal properties. However, in the present study, for the first time in C. vulgaris, CGF was found as a best growth stimulator by enhancing the biomass level (1.208 kg m⁻³) significantly on day 5. Gibberellin and citrate augmented the biomass by 0.935 kg m⁻³ and 1.025 kg m⁻³. Combination of CGF and phytohormones were more effective than CGF and carbon sources. Analysis of fatty acid methyl esters indicated that the ratio of saturated to unsaturated fatty acids is higher in cytokinin, abscisic acid and CGF, and are also rich in short chain carbon atoms, ideal criteria for biodiesel. Nitrogen starvation favoured synthesis of more unsaturated fatty acids than saturated. This study shows that CGF enhances the biomass and lipid significantly and thus can be used for large scale biomass production.     

利用普通小球藻Chlorella vulgaris C9-JN2010处理氨基酸工业废水的研究

用普通小球藻Chlorella vulgaris C9-JN2010处理氨基酸工业废水,实现废水无害化利用。在微型鼓泡式光反应器中,(25±1)℃,pH(6.5±0.5),0.1 vvm空气流速,4 000 lux,16 h:8 h光暗比条件下,分别考察小球藻在体积分数为20%、40%、60%、80%及100%的氨基酸废水中培养生物量变化及TN、TP、COD的去除率。结果表明,体积分数40%氨基酸废水处理效果最好,停留时间3～4 d,藻细胞干重、比生长速率和最大生产强度分别为0.731 g/L、0.565 d-1、0.243 g/(L.d);废水中TN、TP及COD的去除率分别为92.0%、98.0%及80.0%,对应去除强度分别为30.7、3.28、133.3mg/(L.d)。利用小球藻可以较彻底的去除氨基酸废水中氮、磷及COD等营养,达到污水处理效果。     

HZSM-5/MCM-41对小球藻催化热解的影响

以HZSM-5/MCM-41为催化剂,在管式炉内对小球藻进行了催化热解研究。考察了HZSM-5/MCM-41复合催化剂中MCM-41的添加比例对小球藻热解产物影响,并采用GC-MS和元素分析对所制取生物油进行了表征。结果表明:与HZSM-5催化剂相比,90%HZSM-5与10%MCM-41混合后生物油中3,7,11,15-四甲基-2-十六烯的选择性最好。羧酸类和含氮物质分别降低12.85%、43.97%,脂肪烃和芳烃的质量分数之和达到50.34%,且不存在硬脂酰胺和油酸腈等物质。根据元素分析可知,10%的MCM-41的引入使生物油含氧量降低23.52%,O/C原子比明显降低,H/C原子比得到提高,热值达到32.995 MJ·k-1,且油品组成与生物柴油接近。热重实验表明,分子筛催化剂失活主要是由于积炭的产生,HZSM-5/MCM-41具有良好的稳定性。随着催化剂用量的增加,生物油热值增加,同时含水量也增多,HZSM-5/MCM-41与小球藻质量比例为1:5时,生物油产率最高。     

Chlorella vulgaris Attenuates Dermatophagoides Farinae-Induced Atopic Dermatitis-Like Symptoms in NC/Nga Mice

Atopic dermatitis (AD) is a chronic and inflammatory skin disease that can place a significant burden on quality of life for patients. AD most frequently appears under the age of six and although its prevalence is increasing worldwide, therapeutic treatment options are limited. Chlorella vulgaris (CV) is a species of the freshwater green algae genus chlorella, and has been reported to modulate allergy-inducible factors when ingested. Here, we examined the effect of CV supplementation on AD-like symptoms in NC/Nga mice. CV was orally administrated for six weeks while AD-like symptoms were induced via topical application of Dermatophagoides farinae extract (DFE). CV treatment reduced dermatitis scores, epidermal thickness, and skin hydration. Histological analysis also revealed that CV treatment reduced DFE-induced eosinophil and mast cell infiltration into the skin, while analysis of serum chemokine levels indicated that CV treatment downregulated thymus- and activation-regulated chemokine (TARC) and macrophage-derived chemokine (MDC) levels. In addition, CV treatment downregulated mRNA expression levels of IL-4 and IFN-γ. Taken together, these results suggest that CV extract may have potential as a nutraceutical ingredient for the prevention of AD.     

超声强化亚临界CO_2萃取小球藻中叶黄素的研究

采用超声强化亚临界CO2技术研究了从小球藻中萃取叶黄素的工艺条件,并初步分析了超声强化的机理。实验中考察了萃取温度、萃取压力、流体流量、夹带剂用量、萃取时间及超声功率对叶黄素萃取率的影响,得到了最佳的工艺条件:萃取温度25℃,萃取压力11MPa,流体流量30kg/h,夹带剂用量为1.5mL/g的无水乙醇,萃取时间3h,超声功率750W。     

小球藻粉热解及其催化热解试验研究

采用热重分析法考察小球藻粉的热解特性,以HZSM-5、HY分子筛为催化剂,对小球藻粉直接热解和催化热解后生物油的化学组成进行对比分析,研究2种分子筛催化剂对催化热解的影响。结果表明,小球藻粉的热解温度为160～600℃;小球藻粉加入HZSM-5分子筛催化剂催化热解后,十六酸及含氮化合物的含量大幅降低,烃类物质的含量提高,含有较多甲苯、二甲苯等芳香烃;经HY分子筛催化热解后,十六酸含量降低,含氮化合物的含量大幅提高,形成大量的萘等多环芳烃;HZSM-5分子筛具有较好的催化脱氧、择形芳构化功能,HY分子筛择形性较差,导致多环芳烃及含氮化合物的含量提高。     

小球藻培养条件及其抑制α-葡萄糖苷酶活性的研究

通过对小球藻培养条件中初始pH值、接种量、培养温度、光照等因素进行研究,探讨小球藻的最佳培养条件,并对培养的小球藻提取物进行α-葡萄糖苷酶活性抑制实验。结果表明,初始pH值为7,接种量为100:10,培养温度为25℃/20℃(昼/夜),光照强度为10000Lx为小球藻的最佳培养条件;其水提物对α-葡萄糖苷酶活性的IC50值为3.14mg/mL,具有一定的抑制活性。     

含锌重金属废水藻类吸附处理技术

以小球藻为吸附剂,研究藻类吸附剂对重金属废水中Zn2+的吸附过程,分析吸附时间、温度、pH值、Zn2+起始浓度以及预处理过程等因素对小球藻吸附Zn2+性能的影响。结果表明:预处理能提高小球藻的吸附性能,其吸附过程符合Langmuir吸附特征,对废水的pH值适应范围广。对于ρ(Zn2+)=100 mg/L的重金属废水经小球藻一次处理,去除率达到98%。小球藻吸附处理废水中Zn2+的较佳工艺条件为pH值6.5、温度25℃、吸附时间60 min、小球藻用量2 g/L。     

用于与活性污泥共固定化的蛋白核小球藻在不同碳源下的培养研究

在蛋白核小球藻与活性污泥共固定化条件下，采用不同碳源对蛋白核小球藻进行了小型培养和扩大培养．结果显示，测定蛋白核小球藻藻液细胞密度的最佳波长为680nm；含10g/L葡萄糖的Bold培养基培养时表现出适应期较短(20h)、对数期较长(25h)、藻细胞最大生长率高(kmax=0．098h^-1)，且最大生长率出现时间早(第37．5h)等特点．扩大培养研究证实，经过72h培养可以得到10^8个细骨包／mL的藻液．该培养方式可以满足相关的藻类污水生物处理技术研究对藻液的需求．