Induced production of chitinase to enhance entomotoxicity of Bacillus thuringiensis employing starch industry wastewater as a substrate

Induced production of chitinase during bioconversion of starch industry wastewater (SIW) to Bacillus thuringiensis var. kurstaki HD-1 (Btk) based biopesticides was studied in shake flask as well as in computer-controlled fermentors. SIW was fortified with different concentrations (0%; 0.05%; 0.1%; 0.2%; 0.3% w/v) of colloidal chitin and its consequences were ascertained in terms of Btk growth (total cell count and viable spore count), chitinase, protease and amylase activities and entomotoxicity. At optimum concentration of 0.2% w/v colloidal chitin, the entomotoxicity of fermented broth and suspended pellet was enhanced from 12.4 × 10⁹ (without chitin) to 14.4 × 10⁹ SBU/L and from 18.2 × 10⁹ (without chitin) to 25.1 × 10⁹ SBU/L, respectively. Further, experiments were conducted for Btk growth in a computer-controlled 15 L bioreactor using SIW as a raw material with (0.2% w/v chitin, to induce chitinase) and without fortification of colloidal chitin. It was found that the total cell count, spore count, delta-endotoxin concentration (alkaline solubilised insecticidal crystal proteins), amylase and protease activities were reduced whereas the entomotoxicity and chitinase activity was increased with chitin fortification. The chitinase activity attained a maximum value at 24 h (15 mU/ml) and entomotoxicity of suspended pellet reached highest (26.7 × 10⁹ SBU/L) at 36 h of fermentation with chitin supplementation of SIW. In control (without chitin), the highest value of entomotoxicity of suspended pellet (20.5 × 10⁹ SBU/L) reached at 48 h of fermentation. A quantitative synergistic action of delta-endotoxin concentration, spore concentration and chitinase activity on the entomotoxicity against spruce budworm larvae was observed.     

Impact of different pH control agents on biopesticidal activity of<Emphasis Type="Italic"> Bacillus thuringiensis</Emphasis> during the fermentation of starch industry wastewater

Different pH control agents (NaOH/H₂SO₄—SodSulp, NaOH/CH₃COOH—SodAcet, NH₄OH/CH₃COOH—AmmoAcet and NH₄OH/H₂SO₄—AmmoSulp) were used to investigate their effects on growth, enzyme production (alkaline protease and amylase), and entomotoxicity of Bacillus thuringiensis var. kurstaki HD-1 (Btk) against eastern spruce budworm larvae (Choristoneura fumiferana) using starch industry wastewater (SIW) as a raw material in a 15-l fermentor. AmmoSulp and SodSulp were found to be the best pH control agents for alkaline protease and amylase production, respectively; whereas, the fermented broth obtained by using SodAcet as pH control agents recorded the highest delta-endotoxin production of 1043.0 mg/l and entomotoxicity value 18.4 × 10⁹ SBU/l. Entomotoxicity of re-suspended centrifuged pellet in one-tenth of original volume in case of SodAcet as pH control agents was 26.7 × 10⁹ SBU/l and was the highest value compared to three other pH control agents.     

Germanium: environmental occurrence, importance and speciation

This review discusses the various aspects of the bio-geochemistry of germanium, and of its technological, economical and environmental importance. Despite the relatively low annual production and consumption of this semi-metal (ca. 80 metric tons/a) there are important technological applications of this element in the semiconductor, infrared optics and fibre optics/telecommunication industries. A small, but not insignificant fraction of this element is used for the production of pharmaceuticals and nutritional supplements, although its actual merits have not been fully demonstrated yet, while they are opposed to chronic toxicity of the element when being administrated at relatively high doses for an extended period of time. Neither the exact mechanism of action in the case of cancer treatment or the treatment of infectious diseases is known, nor the reason for the toxicity of inorganic species of this element. In plants, Ge can partially substitute for B in the case of boron deficiency, although deficiency symptoms are still seen with a lag period of ca. one to three weeks. In biogeochemical respect, germanium and silicon react very similar, as if Ge were a very heavy isotope of Si. Their molar ratio is typically in the order of 0.6 × 10⁻⁶, with significant deviations only where germanium is complexed and transported, e.g., by humic-rich waters. Germanium is a very conservative element in biogeochemical terms: It hardly shows involvement in any biogeochemical reaction cycles and is mainly present in the form of complexes or hydroxo-compounds of the tetravalent germanium. The only naturally occurring organogermanium compounds are mono- and dimethylgermanium which are believed to be formed by microbiological activity in continental zones containing Ge-rich minerals, and then are leached into rivers, and finally into the open sea. It becomes evident that, although very sophisticated technological uses of germanium exist, a better understanding of its biogeochemical importance, cycling and reactivity must still be developed.     

Isolation and Characterization of A Metal-resistant Pseudomonas Aeruginosa Strain

Summary The use of microorganisms to remove heavy metals from industrial effluent is an area of extensive research and development. Attempts have been made to isolate and characterize metal-resistant microorganisms from treated oil mill industry effluent wastewater samples. The metal-resistant organisms that showed values of minimum inhibitory concentration towards metals (Cd, Cr, Ni and Pb) ranging from 100 to 800 ppm level were screened. A potent metal-resistant organism, isolate BC15 from the wastewater samples was tentatively identified as Pseudomonas sp. Detailed analysis of morphological, biochemical and 16S rDNA sequence of the isolate revealed that it is closely related to Pseudomonas aeruginosa (94%). Pseudomonas BC15 was capable of absorbing 93% Ni, 65% Pb, 50% Cd and 30% Cr within 48 h from the medium containing 100 mg of each heavy metal per liter. The multiple metal tolerance of this strain was also associated with resistance to antibiotics such as ampicillin, tetracycline, chloramphenicol, erythromycin, kanamycin and streptomycin.     

Cork stoppers industry: defining appropriate mould colonization

AIMS: The main aims of this work were the study of cork slabs moulds colonization and the evaluation of the moulds diversity during cork processing steps, in different cork stoppers factories. Simultaneously, it was envisaged to perform an evaluation of the air quality. METHODS AND RESULTS: Moulds were isolated and identified from cork slabs and cork samples in four cork stoppers factories. The identification was based on morphological characters and microscopic observation of the reproductive structures. Airborne spore dispersion was assessed using a two stage Andersen sampler. It was observed that Chrysonilia sitophila was always present on cork slabs during the maturing period, but mould diversity appeared to be associated to the different factory configurations and processing steps. CONCLUSIONS: Spatial separation of the different steps of the process, including physical separation of the maturation step, is essential to guarantee high air quality and appropriate cork slabs colonization, i.e. C. sitophila dominance. The sorting and cutting of the edges of cork slabs after boiling and before the maturing step is also recommended. SIGNIFICANCE AND IMPACT OF THE STUDY: This study is very important for the cork stopper industry as it gives clear indications on how to keep high quality manufacturing standards and how to avoid occupational health problems.     

Who will develop new antibacterial agents?

The golden age of antimicrobial drug development is a distant memory, and the likelihood of there being another seems slim. In part, this is because the pharmaceutical industry, which has now adopted an unsustainable business model, abandoned the anti-infective sector, and the pipeline is almost empty. The contribution to this crisis of national governments, health agencies and funders also merits discussion. Much of the basis for drug discovery is funded by the public sector, thereby generating intellectual property and leads for drug development that are often not pursued owing to funding gaps. In particular, the cost of testing drug efficacy in clinical trials is beyond the means of most companies and organizations. Lack of a concerted international effort to develop new antimicrobials is particularly alarming at a time when multidrug-resistant bacteria threaten all areas of human medicine globally. Here, the steps that led to this situation are retraced, and some possible solutions to the dilemma are proposed.     

我国大型煤炭基地建设的生态恢复技术研究综述

煤炭能源是我国的主体能源,在我国经济社会发展中具有重要的战略地位。煤炭工业是关系我国经济发展和能源供应安全的重要基础产业。由于受传统发展观的影响,煤炭工业一直存在生产粗放、安全事故频发、资源浪费严重、环境治理和管理滞后等问题。我国大型煤炭基地的建设对提高煤炭供应保障能力起到了关键支撑作用。因此,从区域可持续发展的角度出发,加强矿区的生态恢复,深化煤炭资源的开发利用和环境保护,对促进国家和区域生态环境与社会经济的可持续发展,构建和谐矿区,确保区域乃至全国的生态安全特别是能源安全具有重要的意义。介绍了国家大型煤炭基地的发展历程、分布和开发现状,以及煤炭开采利用带来的一系列生态环境问题,重点阐述了当前我国煤炭基地建设的关键生态恢复技术体系,并从生态恢复与环境管理的角度提出我国大型煤炭基地的可持续发展建议。     

2014生物质炼制专刊序言

生物质是自然界最丰富的含碳有机大分子功能体,它有望通过"生物炼制"实现"石油炼制"的辉煌。但是由于生物质资源本身及其转化过程的复杂性,生物质产业虽备受关注,却被认为是遥远的未来产业。传统的生物质资源化利用思路都是先耗费一定的能量破坏生物质结构,然后再进行转化,不仅没有考虑到产品的功能需求,而且过程的原子经济性不高。如何实现化学键更加复杂的固相木质纤维素生物质炼制是实现生物质产业的关键和难点。理想的生物质炼制的目的是以最大得率分离木质纤维原料中各个组分,以尽可能地保持分子的完整性,最大可能地优化利用和最终实现最大价值。这就要求生物质炼制应当是基于原料结构、过程转化和产品特点三者的关联,面向原料、面向过程、面向产品的炼制过程。本期专刊报道了我国生物质炼制技术领域专家学者在原料炼制、炼制技术、组分转化等领域取得的最新研究进展。     

Endotoxin inactivation via steam‐heat treatment in dilute simethicone emulsions used in biopharmaceutical processes

Simethicone emulsion is used to regulate foaming in cell culture operations in biopharmaceutical processes. It is also a potential source of endotoxin contamination. The inactivation of endotoxins in dilute simethicone emulsions was assessed as a function of time at different steam temperatures using a Limulus amebocyte lysate kinetic chromogenic technique. Endotoxin inactivation from steam‐heat treatment was fit to a four‐parameter double exponential decay model, which indicated that endotoxin inactivation was biphasic, consisting of fast and slow regimes. In the fast regime, temperature‐related effects were dominant. Transitioning into the slow regime, the observed temperature dependence diminished, and concentration‐related effects became increasingly significant. The change in the Gibbs free energy moving through the transition state indicated that a large energy barrier must be overcome for endotoxin inactivation to occur. The corresponding Arrhenius pre‐exponential factor was >>10¹² s^?1 suggesting that endotoxins in aqueous solution exist as aggregates. The disorder associated with the endotoxin inactivation reaction pathway was assessed via the change in entropy moving through the transition state. This quantity was positive indicating that endotoxin inactivation may result from hydrolysis of individual endotoxin molecules, which perturbs the conformation of endotoxin aggregates, thereby modulating the biological activity observed. Steam‐heat treatment decreased endotoxin levels by 1–2 logarithm (log) reduction (LRV), which may be practically relevant depending on incoming raw material endotoxin levels. Antifoam efficiency and cell culture performance were negligibly impacted following steam‐heat treatment. The results from this study show that steam‐heat treatment is a viable endotoxin control strategy that can be implemented to support large‐scale biopharmaceutical manufacturing. © 2014 American Institute of Chemical Engineers Biotechnol. Prog., 30:1145–1160, 2014