Evaluating Cell Disruption Strategies for Aqueous Lipid Extraction from Oleaginous Scenedesmus obliquus at High Solid Loadings

Among various renewable energy sources, the production of biofuels derived from algal lipids holds bright prospects. One of the major roadblocks in the successful commercialization of microalgal biofuels is the existing energy‐intensive lipid extraction. In the present investigation, an attempt is made to assess aqueous lipid extraction strategies from oleaginous Scenedesmus obliquus at a high solid loading of 15% (w/v). In this study, four surfactants and five enzymes are evaluated for cell disruption of S. obliquus. It is the first report citing cetyl pyridinium bromide as the most suitable cationic detergent for surfactant‐assisted extraction, with a lipid recovery as high as 31.4%. However, during the evaluation of enzyme‐based cell disruption, neutral protease emerges as the best biocatalyst resulting in a lipid recovery of ≈75%. Total lipid extraction is accomplished using a two solvent system comprising of water‐immiscible ethyl acetate, followed by chloroform addition. The study revalidates the fact that the biochemical composition of Scenedesmus sp. plays a vital role while identifying and formulating an efficient and green process for microalgal cell disruption for enhanced lipid extraction under aqueous conditions. Practical Applications: The results of the present study demonstrate that if the biochemical composition of any oleaginous algal cell wall is known, aqueous enzymatic lipid extraction can be employed rather than taking up the conventional route of drying followed by Soxhlet extraction. The combination of using the cheap sources of enzymes and water‐immiscible green solvents like ethyl acetate can be lucrative downstream procedures for the lipid recovery from wet algal biomass when compared to traditional procedures.     

Biological Synthesis of Bioactive Gold Nanoparticles from Inonotus obliquus for Dual Chemo-Photothermal Effects against Human Brain Cancer Cells

The possibility for an ecologically friendly and simple production of gold nanoparticles (AuNPs) with Chaga mushroom (Inonotus obliquus) (Ch-AuNPs) is presented in this study. Chaga extract’s reducing potential was evaluated at varied concentrations and temperatures. The nanoparticles synthesized were all under 20 nm in size, as measured by TEM, which is a commendable result for a spontaneous synthesis method utilizing a biological source. The Ch-AuNPs showed anti-cancer chemotherapeutic effects on human brain cancer cells which is attributed to the biofunctionalization of the AuNPs with Chaga bioactive components during the synthesis process. Further, the photothermal ablation capability of the as-prepared gold nanoparticles on human brain cancer cells was investigated. It was found that the NIR-laser induced thermal ablation of cancer cells was effective in eliminating over 80% of the cells. This research projects the Ch-AuNPs as promising, dual modal (chemo-photothermal) therapeutic candidates for anti-cancer applications.     

Optimization of flocculation with tannin-based flocculant in the water reuse and lipidic production for the cultivation of Acutodesmus obliquus

This paper evaluated the optimization of natural flocculant in different conditions in a tubular photobioreactor using swine wastewater effluent as culture media in a pilot-scale microalgae production plant. This study aimed to assess the flocculation efficiency of Tanfloc SG via a central composite design (CCD), with varying Tanfloc SG concentration, biomass concentration and pH. Subsequently, the microalga Acutodesmus obliquus was cultivated in medium obtained from the recycled recovery of microalgae cells via flocculation with Tanfloc SG. Results showed that the recycled medium after flocculation with Tanfloc SG had a positive effect on the biomass and lipid production of A. obliquus.     

高效氯氰菊酯对斜生栅藻的毒性研究

以斜生栅藻细胞的生长状况、光合色素(叶绿素a、叶绿素b、类胡萝卜素)及蛋白质含量的变化作为指标,研究了不同质量浓度的高效氯氰菊酯对斜生栅藻的毒性效应.24 h、48 h、72 h、96 h的EC50(mg·mL-1)分别为11.71、6.19、4.03、2.87,斜生栅藻生长受抑制程度随高效氯氰菊酯质量浓度增加而加强,当高效氯氰菊酯的质量浓度超过10 mg·L-1时,斜生栅藻的生长几乎完全受到抑制.染毒96 h的斜生栅藻光合色素(叶绿素a、叶绿素b、类胡萝卜素)含量以及蛋白质含量随着高效氯氰菊酯的质量浓度的增加呈下降趋势,其中叶绿素a受到的影响最大.     

基于响应面法的闪式提取桦褐孔菌多糖工艺优化

利用响应面法优化桦褐孔菌多糖的闪式提取工艺。在单因素实验的基础上,以桦褐孔菌多糖的提取率为响应值,以料液比、提取时间、提取电压为主要考察因素,采用响应面法优化闪式提取桦褐孔菌多糖的最佳工艺参数。结果表明,经响应面优化得到料液比为1∶23,提取时间为86 s,提取电压为150 V时,桦褐孔菌多糖的提取率最高,可达到8.52%。结论:闪式提取法适用于桦褐孔菌多糖的提取,该工艺具有方便、快速和高效的优点。且经响应面法优化所得的最佳提取条件准确可靠,具有一定的实用价值。      

桦褐孔菌的化学成分与药理作用研究

桦褐孔菌是一种食用真菌,主要含有羊毛甾醇型三萜类、桦褐孔菌醇和桦褐孔菌素、黑色素类、叶酸衍生物,以及芳香物质、木质素、栓菌酸、单宁等化学成分,其中起主要药理作用的为羊毛甾醇型三萜类、桦褐孔菌醇、桦褐孔菌素和木质素.具有抵抗肝癌、胃癌、肺癌、宫颈癌、乳腺癌、皮肤癌、直肠癌、淋巴等多种肿瘤细胞,以及抗艾滋病病毒、抗感染、治疗糖尿病、降血压调节血脂、抗机体衰老、增强免疫力等药理作用.应该利用现代技术手段和方法,以循证医学的观念,加强对桦褐孔菌的深入研究,充分发挥其药用价值.     

桦褐孔菌多酚的液体深层制备及抗氧化活性研究

用液体深层发酵方式培养并提取了不同时间的桦褐孔茵胞内外多酚,福林-酚法测定桦褐孔茵胞内外多酚的含量,通过清除DPPH·自由基和羟基自由基测定桦褐孔茵多酚的抗氧化活性,液质联用技术测定了胞内外多酚的基本组成和含量.结果表明,桦褐孔茵胞内外多酚最大含量分别为12.47 mg GAE/g和34.7 mg GAE/L,DPPH·自由基的最大清除率分别为52.5％和54.6％,羟基自由基的清除率为80.5％和66.2％,液质联用检测结果显示胞内外多酚含量分别为96.4％和86.3％,且种类和单一组分含量差异显著.     

斜生栅藻对乙酰甲胺磷的急慢性毒性响应

为了解有机磷农药乙酰甲胺磷污染对本土水生敏感性物种斜生栅藻（ Scenedesmus obliquus）的毒性效应,在实验室条件下采用静态毒性试验,研究了乙酰甲胺磷对斜生栅藻96 h急性毒性效应,并在急性试验基础上进行慢性试验,分析了斜生栅藻连续染毒14 d的叶绿素质量浓度、可溶性蛋白质量分数以及丙二醛（ MDA）质量摩尔浓度的变化．结果表明：乙酰甲胺磷的96 h EC50为482.9 mg/L,属低毒农药,但在1 mg/L低质量浓度下可促进藻细胞生长;乙酰甲胺磷对栅藻光合作用无明显影响,但可通过干扰藻细胞代谢活动和引起膜脂过氧化反应,对斜生栅藻产生毒性作用;可溶蛋白和MDA可作为有效的生物标志物对农药引起的毒性做出评价．研究结果可为本土水生敏感性物种的保护和农药安全使用标准的制定提供理论依据．     

桦褐孔菌多糖涂膜对苹果保鲜效果的研究

采用不同浓度的桦褐孔菌多糖保鲜液对苹果进行涂膜处理,5℃低温下贮藏,研究桦褐孔菌多糖对苹果的保鲜效应。结果表明:2%～6%桦褐孔菌多糖保鲜液对苹果有良好的保鲜效果,能够降低苹果的失重率、腐烂率和呼吸强度,保持其硬度,抑制PPO活性和微生物生长繁殖,其中6%的桦褐孔菌多糖保鲜液效果最好。