Biocatalytic Synthesis of the Anti‐diabetes Agent‐corosolic Acid by Whole Cells of Microorganisms

Diabetes is one of the most prevalent and costly global diseases. For diabetes, frequent insulin treatment and synthetic drugs are very expensive and may cause unwanted side effects. Corosolic acid (CA), a natural product, was reported to be efficient in the treatment of diabetes, meanwhile without induction of anti‐insulin antibodies and obesity. The preparation of CA attracted many researchers in the world. This study investigated the biocatalytic synthesis method of CA from ursolic acid by Streptomyces griseus subsp. griseus 4.18. LC? MS analysis demonstrated that 5 day, 125 μg/mL substrate, pH=9 and 10% strain concentration were the appropriate conditions. It is estimated that biocatalysis will contribute to the development of green and sustainable synthetic processes with less time‐consuming and more environmentally friendly.     

Thermosonication as a potential quality enhancement technique of apple juice

Enzymatic browning and microbial growth lead to quality losses in apple products. In the present study, fresh apple juice was thermosonicated using ultrasound in-bath (25 kHz, 30 min, 0.06 W cm⁻³) and ultrasound with-probe sonicator (20 kHz, 5 and 10 min, 0.30 W cm⁻³) at 20, 40 and 60 °C for inactivation of enzymes (polyphenolase, peroxidase and pectinmethylesterase) and microflora (total plate count, yeast and mold). Additionally, ascorbic acid, total phenolics, flavonoids, flavonols, pH, titratable acidity, ^°Brix and color values influenced by thermosonication were investigated. The highest inactivation of enzymes was obtained in ultrasound with-probe at 60 °C for 10 min, and the microbial population was completely inactivated at 60 °C. The retention of ascorbic acid, total phenolics, flavonoids and flavonols were significantly higher in ultrasound with-probe than ultrasound in-bath at 60 °C. These results indicated the usefulness of thermosonication for apple juice processing at low temperature, for enhanced inactivation of enzymes and microorganisms.     

近红外光谱技术在微生物检测中的应用进展

近红外光谱作为一种无损检测技术被广泛应用于农业、制药、食品等领域的多组分品质快速监测。微生物的快速准确检测,在临床诊断、制药和食品加工等领域一直是一个难题。微生物菌体细胞壁、细胞膜及细胞内生物大分子和水的近红外光谱具有高度特异性,因此可以使用近红外光谱快速识别和分类不同的微生物。通过对相关文献的归纳整理与分析提炼,对近红外光谱技术在微生物检测中的研究进展做综述。对微生物的基本知识和近红外光谱技术鉴定微生物的基本原理进行了介绍,并重点综述了近红外光谱技术在微生物分类、食源性微生物检测和成像微生物检测等方面的国内外研究进展,最后对近红外光谱技术目前存在的问题和未来的应用前景进行了展望,以期为今后在微生物检测领域更好地利用近红外光谱提供参考。     

微生物接种堆肥胡敏酸三维荧光特性研究

为提高堆肥效率,试验采用接种微生物堆肥技术,通过对堆肥样品中胡敏酸三维荧光光谱特性进行动态分析,探讨了微生物接种对堆肥腐殖化进程的影响。在堆肥初期,胡敏酸只产生一个类富里酸荧光峰(peak a,Ex/Em为330/440)。在堆肥的336 h,与对照(RUN_ck)相比,接种微生物堆肥(RUN_mic)胡敏酸三维荧光光谱中类富里酸特征峰(peak a,Ex/Em约为350/440)荧光强度明显减少,而类胡敏酸荧光峰(peak b,Ex/Em约为390/470)强度则略有增加;并且peak a和peak b对应的激发、发射波长均有一定程度的红移。胡敏酸元素分析表明,堆肥336 h,RUN_ck胡敏酸分子中C/H和O/C依次增加9.68%和10.91%;RUN_mic中胡敏酸C/H和O/C依次增加了11.11%和20.37%,表明RUN_mic中胡敏酸分子缩合度明显。以上结果证实,接种微生物可明加快堆肥腐殖化进程,进而提高堆肥效率。     

Biofuel Cells for Self‐Powered Electrochemical Biosensing and Logic Biosensing: A Review

This article reviews recent advances and progress in developing electrochemical (EC) biosensing and logic biosensing systems based on self‐powered biofuel cells (BFCs). BFCs that exploit enzymes and microbes have attracted a considerable recent interest owing to their unique ability to provide sustainable energy from renewable fuel source under mild conditions. This review focuses on recently introduced novel concepts for using BFCs as the basic element for EC‐biosensing and especially EC‐logic biosensing applications. The fabrication and design of such self‐powered EC‐biosensing and EC‐logic biosensing are described along and different new approaches for BFCs‐based EC‐biosensing and EC‐logic biosensing involving substrate effects, inhibition effects, blocking effects and gene regulation effects. Latest advances in coupling a self‐powered diagnostic operation with logic‐activated drug release functionality are discussed. We conclude with the implications of the new self‐powered biosensing/logic‐biosensing platforms along with future prospects and challenges.