Enhanced enzymatic hydrolysis of hydrothermally pretreated empty fruit bunches at high solids loadings by the synergism of hemicellulase and polyethylene glycol

In enzymatic hydrolysis, high lignocellulose loadings are required to obtain high sugar titers. However, the high solids loadings limit enzymatic hydrolysis. In this study, to overcome this limitation, the promoting and synergistic effects of the accessory agents of hemicellulase (i.e., Cellic HTec2) and polyethylene glycol (PEG) 8000 were investigated in the enzymatic hydrolysis of hydrothermally pretreated empty fruit bunches (EFBs). After the optimal addition of Cellic HTec2 and PEG, high enzymatic digestion of the pretreated EFBs was achieved owing to their synergistic effects, even at high solids loadings. For example, the enzymatic digestibility of pretreated EFBs at a 21.7% (w/v) solids loading with 10 FPU of Cellic CTec2/g glucan reached 72.5% when 2.7 mg of Cellic HTec2/g glucan and 62.5 mg of PEG/g glucan were used as the accessory agents. These results suggested that the optimal addition of accessory agents is effective for the enhanced hydrolysis of lignocellulose using even a commercial cellulase preparation.     

Zum 70. Geburtstag Von Professor Dr. Habil. Theo Wetzel

Information on the structure of the population of Phomopsis species in Ukraine, that describes the structure of Phomopsis spp. cultivated on medium: the morfological characteristics, properties of pathogenicity and phytotoxicity. It is described the method of evaluation and selection of unsusceptible forms of sunflower to phomopsis. It includes the optimal infection level, the forms of an inoculum that is effective and optimal way for artificial infection.     

NaCl预处理提高两种铁线子属果树耐寒性的研究

古巴牛乳树和人心果是铁线子属具有开发前景的热带珍稀果树。为了将这两种果树在亚热带地区推广种植,该研究在已知这两种果树具有较高耐盐性的研究基础上,采用盆栽试验法,对3年生幼苗设置10‰、20‰的Na Cl预处理,一定时间后依次进行9℃、3℃的低温胁迫,分析比较其叶片中多种渗透调节物质含量及抗氧化酶活性的变化。结果表明:两种果树叶片渗透调节物质含量及抗氧化酶活性的变化趋势是一致的。在9℃、3℃的低温胁迫下,10‰、20‰Na Cl预处理叶片中的游离脯氨酸、可溶性糖和可溶性蛋白质含量及超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性均明显高于对照组,同一低温条件下,耐寒性强弱依次为10‰20‰对照(CK)。因此推断Na Cl预处理可以有效提高铁线子属果树的耐寒性,其中以10‰预处理最为理想,此时古巴牛乳树和人心果的实际盆土盐度分别为2.46‰、1.14‰。     

Transient β-glucuronidase activity after infiltration of Arabidopsis thaliana by Agrobacterium tumefaciens

Transient expression of the β-glucuronidase (GUS) gene introduced into Arabidopsis thaliana intact plants by T-DNA after vacuum infiltration of Agrobacterium tumefaciens was followed. The first incidence of GUS activity was found 2 - 3 d after treatment and a peak of activity one week after treatment in both A. thaliana races, Columbia and C24. GUS activity was sharply increased by cultivation of Arabidopsis plants at elevated temperature (29 °C) compared to cultivation at 25 °C. The density of inocula also influenced the GUS activity. This revised version was published online in July 2006 with corrections to the Cover Date.     

Diaphragms and flooding survival

Why don't the gas spaces of submerged organs of wetland plants flood extensively when damaged? In addressing this intriguing question, Soukup et al . (pp. 71–75 in this issue) report on the role of rhizome diaphragms as barriers to flooding in Phragmites australis . This should prompt some reappraisal of the ways in which flooding resistance can be realized, even perhaps in undamaged organs.
Most emergent wetland macrophytes have an abundance of interconnected internal gas space, much of it in the form of large voids transversely partitioned at intervals by perforated cellular plates termed diaphragms. Functionally, it provides a low-resistance pathway for internal oxygen transport to support the respiratory needs of submerged and buried organs (Armstrong, 1979; Armstrong et al ., 1988; Crawford, 1992) and facilitates carbon dioxide removal. However, it does more than this, since it enables oxygen to be released from the root to where it can support aerobic microbial activity in otherwise anaerobic sediments, and phytotoxin immobilization or destruction (Armstrong et al ., 1992; Begg et al ., 1994; Gilbert & Frenzel, 1998). This oxygen release is regarded by some as a valuable aid to effluent purification by constructed wetlands. Perhaps a less desirable property of this gas-space provision is its recently discovered role in enhancing the emissions of greenhouse gases such as methane from wetlands (Brix et al ., 1992; Chanton & Whiting, 1996; Crutzen, 1991; Dacey & Klug, 1979).     

Effect of Rotylenchulus reniformis on Yield and Nitrogen,Potassium, Phosphorus and Amino Acid Content of Seed of Glycine max

Soybean cultivars varied in their response and tolerance to low initial Rotylenchulus reniforrnis populations of 10,000 nematodes/3.8 liters of soil, but a high initial population of 25,000 consistently reduced yields on resistant and susceptible cultivars by an average of 33.1%. At the 10,000 nematode inoculum level, dry seed yields of Hood decreased while those of Pickett increased significantly. Generally, total phosphorus decreased 11.1 and 11.5% and potassium increased 5.9 and 4.5% in seeds harvested from plants receiving initial inoculum levels of 5000 and 10,000 nematodes/pot, respectively. Little change in the total nitrogen content in seed was noted. Leucine content of seeds from infected plants was slightly less than from noninfected plants.     

Isolation of polyphenols from spent coffee grounds and silverskin by mild hydrothermal pretreatment

In this study, a new method for isolation of polyphenols (PP) from spent coffee grounds (SCG) and coffee silverskin (CS) is described. The method consisted of a mild hydrothermal pretreatment at 120°C, for 20 min, using a liquid-to-solid ratio of 20 mL/g. PP (determined as gallic acid equivalents, GAE) were the most abundant components in the extracts produced by this method, corresponding to 32.92 mg_GAE/g_SCG and 19.17 mg_GAE/g_CS, among which flavonoids corresponded to 8.29 and 2.73 mg quercetin equivalents/g of SCG and CS, respectively. Both extracts presented antioxidant activity but the results were higher for SCG extract, probably due to the highest content of PP present. Negligible effects (less than 1% solubilization) were caused by the hydrothermal pretreatment on cellulose, hemicellulose, and protein fractions of these materials. Some mineral elements were present in the extracts, with potassium being the most abundant. Hydrothermal pretreatment under mild conditions was demonstrated to be an efficient method to recover antioxidant PP from coffee residues.     

Enhanced poly(L-malic acid) production from pretreated cane molasses by Aureobasidium pullulans in fed-batch fermentation

Poly(L-malic acid) (PMA) is a natural polyester with many attractive properties for biomedical application. However, the cost of PMA production is high when glucose is used as a carbon source. To solve this problem, cane molasses as a low-cost feedstock was applied for the production of PMA. Six pretreatment methods were applied to cane molasses before fermentation. Pretreatment with combined tricalcium phosphate, potassium ferrocyanide, and sulfuric acid (TPFSA) removed significant amounts of metal ions from cane molasses. The PMA concentration increased from 5.4?g/L (untreated molasses) to 36.9?g/L (TPFSA-pretreated molasses) after fermentation in shake flasks. A fed-batch fermentation strategy was then developed. In this method, TPFSA-pretreated cane molasses solution was continuously fed into the fermentor to maintain the total sugar concentration at 20?g/L. This technique generated approximately 95.4?g/L PMA with a productivity of 0.57?g/L/hr. The present study indicated that fed-batch fermentation using pretreated cane molasses is a feasible technique for producing high amounts of PMA.     

Ectomycorrhizal fungi of Pinus pinea L. in northeastern Spain

 Although Pinus pinea L. is an important forest species in the Mediterranean region, few reports exist on its ectomycorrhizal associates. Sixty isolates, obtained from fungal sporocarps collected in mixed forests of P. pinea in Catalonia (northeastern Spain), were tested for ectomycorrhiza formation on containerized P. pinea seedlings when applied as mycelial inoculum produced in peat-vermiculite. A total of 17 isolates, in 8 genera (Amanita, Hebeloma, Laccaria, Lactarius, Pisolithus, Rhizopogon, Scleroderma and Suillus), formed ectomycorrhizas and the percentages of mycorrhizal short roots varied among isolates and species from 13% to 89%. Some of these fungi are cited for the first time in association with P. pinea. The results indicate further fungal candidates for controlled inoculation of P. pinea seedlings in the nursery. Accepted: 29 October 1998