A diazotrophic bacterial endophyte isolated from stems of Zea mays L. and Zea luxurians Iltis and Doebley

The apoplastic fluids of field-grown Zea mays and Zea luxurians plants were isolated from surface sterilized stem tissue by centrifugation and spread on agar plates containing a nitrogen-free, defined medium. The predominant bacterium isolated from these plates was characterized further. The ability of this bacterium to fix nitrogen was confirmed by its ability to grow on a semi-solid, nitrogen-free medium and reduce ¹⁵N₂ to ¹⁵NH₃ and acetylene to ethylene. Protions of the nifH and 16S rRNA genes from this organism were amplified by PCR and sequenced. The nifH gene, which codes for dinitrogenase reductase, from this organism is closely related to nifH from Klebsiella pneumoniae. Similarly, the 16S rRNA gene sequences and carbon utilization tests grouped it closely with K. pneumoniae. Based an these data, the isolates from Z. mays and Z. luxurians are tentatively classified as Klebsiella spp. (Zea). The ability of this bacterium to contribute to the nitrogen economy of the corn plant is unknown.     

Implementing an energetic life cycle analysis to prove the benefits of lignocellulosic feedstocks with protein separation for the chemical industry from the existing bioethanol industry

The biofuel ethanol is currently being produced in large quantities from corn in the US and from wheat in the EU and further capacity expansion is expected. Relying on the so-called 1st generation technology, only the starch contained in the edible portion of the crops (ears/grains) is subjected to fermentation. Following life cycle calculations reveals minute levels of fossil fuel replacement placing doubt on its renewability and an imbalance on the domestic animal feed markets are immerging due to the by-product distiller grains. Additional utilization of the lignocellulosic and protein components of the by-product through new developments has the potential to alleviate both setbacks. A cradle-to-factory gate analysis was performed on a variety of bioethanol production layouts incorporating the newest technological developments to determine the maximum fossil fuel reduction potential. Expanding to include lignocellulose pretreatment for ethanol production with protein separation for amine-based chemical production can increase the fossil fuel mitigation potential by seven- to ninefold for US-corn and five- to eightfold for EU-wheat bioethanol facilities.     

A cost effective fermentative production of succinic acid from cane molasses and corn steep liquor by Escherichia coli

AIM: Development and optimization of an efficient and inexpensive medium for succinic acid production by Escherichia coli under anaerobic conditions. METHODS AND RESULTS: Initially, 0.8 gl(-1) of succinic acid was produced in 60 h in 300-ml medium. On optimization, glucose and peptone were replaced by cane molasses and corn steep liquor. Three hundred ml of this medium was inoculated with 4% (v/v) of seed inoculum, incubated at 39 degrees C for 72 h, resulted in 7.1 gl(-1) of succinic acid in 36 h. Scale up in a 10-l fermentor under conditions of controlled pH and continuous CO2 supply in this medium resulted in 17 gl(-1) of succinic acid in 30 h. CONCLUSIONS: A ninefold increase in succinic acid production was obtained in 500-ml anaerobic bottles with optimized medium having cane molasses and corn steep liquor as against initial medium containing glucose and peptone. However, a subsequent scale up in a 10-l fermentor resulted in a 2.5-fold increase in succinic acid production as against optimized medium used in 500-ml anaerobic bottles. SIGNIFICANCE AND IMPACT OF THE STUDY: Succinic acid production was enhanced in medium consisting of inexpensive carbon and nitrogen sources in a shorter span of time.     

RFLP mapping of the sugary enhancer1 gene in maize

RFLP marker data from an F₂₃ population derived from a cross between a sugary1 (su1) and a sugary enhancer1 (su1, sel) inbred were used to construct a genetic linkage map of maize. This map includes 93 segregating marker loci distributed throughout the maize genome, providing a saturated linkage map that is suitable for linkage analysis with quantitative trait loci (QTL). This population, which has been immortalized in the form of sibbed F₂₃ families, was derived from each of the 214 F₂ plants and along with probe data are available to the scientific community. QTL analysis for kernel sucrose (the primary form of sugar) concentration at 20 days after pollination (DAP) uncovered the segregation of seven major QTL influencing sucrose concentration; a locus linked to umc36a described the greatest proportion of the variation (24.7%). Since maltose concentration has previously been reported to be associated with the se1 phenotype, an analysis of probe associations with maltose concentration at 40 DAP was also conducted. The highly significant association of umc36a with maltose and sucrose concentrations provided evidence that this probe is linked to se1. Phenotypic evaluation for the se1 genotype in each F₂₃ family enabled us to map the gene 12.1 cM distal to umc36a. In contrast to previous work where se1 was reported to be located on chromosome four, our data strongly suggest that the sugary enhancer1 locus maps on the the distal portion of the long arm of chromosome 2 in the maize genome.     

Chilo partellus (Swinhoe) (Lepidoptera: Pyralidae) a new invasive species in Israel

Chilo partellus, the spotted stem borer (SSB), is reported for the first time from the fields of sorghum and corn in Israel. Spotted stem borer larvae were first discovered in July 2010 on sorghum and corn plants in the Western Galilee. The new pest had spread all over northern Israel by the end of 2011. The identity of the new pest was confirmed using the morphology of the dissected male genitalia and its attraction to SSB sex pheromone.     

壳聚糖对玉米生长的调节作用

应用壳聚糖衍生物羧甲基壳聚糖(NCMC)水溶液处理玉米种子,能够促进玉米种子的萌发,提高发芽势和发芽率.处理玉米果穗能够提高玉米未成熟籽粒的可溶性蛋白以及成熟种子的贮藏蛋白含量.以上结果表明,羧甲基壳聚糖对作物生长有调节功能.本文还初步研究了羧甲基壳聚糖对作物生长调控的机理.     

Screening microbial strain for improving the nutritional value of wheat and corn straws as animal feed

From 18 strains of cellulolytic microorganisms including bacteria and filamentous fungi, one strain of soft rot fungus identified as Chaetomium cellulolyticum was screened with respect to stronger decomposition ability of cellulose and hemicellulose and its ability for protein synthesis. As it grew on raw corn straw in solid layer fermentation (SLF) for 5 days, the amino acid content in the fermentation product attained 19.29% (w/w) from 6.43% while the total cell wall was reduced by 54%. A toxicity test with mice showed that the fermentation product is not poisonous. The two filamentous fungi, Trichoderma pseudokoningii S-38 and Penicillium decumbens JU-A10 produced large amounts of extracellular cellulase and hemicellulase in the SLF process, but their growth was limited and they sporulated profusely with regard to their value as animal feed products.     

蛋白酶产生菌LN01水解玉米黄粉蛋白的研究

玉米黄粉中含有约质量分数60%的蛋白质,但很难直接应用,必须进行预处理.本文以玉米黄粉为原料,利用蛋白酶产生菌LN01进行液体发酵,分别研究了液体接种量、初始pH、培养温度和培养时间等因素对LN01菌株水解玉米黄粉蛋白的影响.实验结果表明,LN01菌株水解玉米黄粉蛋白的最佳发酵条件为:初始pH值为6.0,液体种子接种量...     

白腐菌胞外提取液与纤维素酶对玉米秸秆的协同酶解研究

通过评价几株白腐菌固体发酵不同时间的胞外提取液与纤维素酶同时加入对玉米秸秆酶解产糖的影响,得到一个较高糖化效果的胞外降解体系,并对其相关影响因素进行研究,进而初探其协同酶解的机制.结果表明,Echinodontium taxodii 2538固体培养5 d的胞外提取液与纤维素酶形成的胞外降解体系的协同酶解效果较好,酸处...     

转基因抗虫棉种植面积变化对花生田棉铃虫种群影响

【目的】棉铃虫Helicoverpa armigera(Hübner)是花生田主要害虫之一。转基因抗虫棉全面推广后,棉铃虫种群(包括棉田、花生田、玉米田)得到有效控制。近年,随着转基因抗虫棉种植面积逐年下降,花生田棉铃虫种群呈现逐年上升趋势。【方法】本文通过调查山东省花生主产区(非棉区)龙口、招远、莱阳、文登四个县级市花生田棉铃虫成虫、卵量、幼虫量等的发生情况,分析了棉铃虫发生面积及种群数量15年(2000—2014年)的变化规律,并重点分析了主要影响因素。【结果】结果表明:花生棉铃虫发生面积受棉花种植面积影响较大,二者呈显著负相关性;花生田棉铃虫累计诱蛾量总体呈下降趋势,但与棉花种植面积相关性不显著;棉铃虫卵量、虫量与抗虫棉种植面积呈显著负相关性。【结论】所以,转基因抗虫棉种植面积减少是导致花生田棉铃虫种群数量上升的主要因素。另外,近年玉米田棉铃虫发生面积也呈逐年上升趋势,与抗虫棉种植面积呈显著负相关。所以,随转基因抗虫棉种植面积的下降,若不采取有效措施,棉铃虫种群可能会出现大发生趋势。