World Journal of Microbiology and Biotechnology

Production of feruloyl esterases (FAEs) by Fusarium oxysporum was enhanced by optimization of initial pH of the culture medium, the type and concentration of nitrogen and carbon source. Submerged batch cultivation in a laboratory bioreactor (17 l) produced activity at 82 nkat g−1 dry substrate (corn cobs) which compared favorably to those reported for the other microorganisms. Use of de-esterified corn cobs as carbon source decreased FAE production by 5.5-fold compared to untreated corn cobs even though ferulic acid (FA) was added to the concentration found in alkali-extracts of corn cobs. Production of FAE does not therefore, require FA, however, production is diminished by the removal of esterified FA from the growth substrate. Optimal FAE activity was observed at pH 7 and 50 °C with 68 and 55% activity at pH 8 and pH 9, respectively. The esterase was fully stable at pH 5–8 and up to 40 °C and retained 72 and 40% of its activity after 6 h at pH 9 and pH 10, respectively. After separation by isoelectric focusing electrophoresis, a zymogram indicated one major FAE activity exhibiting pI value of 10.5.

An understanding of how the Earth's chemosphere was transformed to a biosphere is central to our understanding of the origin of life and the search for extraterrestrial life or life signatures. Once early prokaryotic life originated and colonized the Earth, the biosphere was well on its way to being formed. In this paper, information and knowledge is integrated to examine the possibility how life first self-assembled and transformed a lifeless chemosphere into a complex biosphere that we still do not understand today.

One hundred and fifteen Saccharomyces cerevisiae strains from Aglianico del Vulture, a red wine produced in Southern Italy, were characterized for the production of some secondary compounds involved in the aroma and taste of alcoholic beverages. The strains exhibited a uniform behaviour in the production levels of n-propanol, active amyl alcohol and ethyl acetate, whereas isobutanol, isoamyl alcohol and acetaldehyde were formed with a wide variability. Only five strains produced wines close to the reference Aglianico del Vulture wine for the traits considered. Of these, two strains were selected, underwent to tetrad analysis and the single spore cultures were tested in grape must fermentation. The progeny of one strain showed a significant metabolic variability, confirming the necessity to test starter cultures for the segregation of traits of technological interest. Our findings suggest the selection of specific strains for specific fermentations as a function of the vine variety characteristics in order to take the major advantage from the combination grape must/S. cerevisiae strain.

The production of volatile compounds by 24 strains of Saccharomyces cerevisiae and one strain each of Candida apicola, C. famata, C. guilliermondii, Hanseniaspora occidentalis, Pichia subpelicullosa and Schizosaccharomyces pombe was evaluated with respect to the production of cachaça. They were isolated from small cachaça distilleries (27), industrial cachaça distilleries (2) and one sugarcane alcohol distillery, and tested in synthetic medium for the production of acetaldehyde, ethyl acetate, propanol, isobutanol, isoamyl alcohol, acetic acid and glycerol. The Saccharomyces strains showed a narrow range of variation in the production of such compounds, near 50% of the average of each volatile compound concentration. Principal component analysis showed the separation of the strains into six groups, and acetic acid production was the variable of greatest impact in the differentiation of the strains. The strains of S. pombe formed a distinct group (Group 2), and the strains of C. apicola and H. occidentalis formed a joint group (Group 6) as did Sc13 and Sc4 (Group 4). Group 1 was formed exclusively of S. cerevisiae. The closest non-Saccharomyces strains were C. apicola and H. occidentalis, with a similarity index of about 0.95. The strain P. subpelliculosa showed general characteristics more similar to those of the S. cerevisiae strains than to the non-Saccharomyces strains.

The principal agent in winemaking is the yeast Saccharomyces cerevisiae, which is characterized by a significant strain biodiversity. Here we report the characterization of 80 wild S. cerevisiae strains, isolated from grapes of different varieties in southern Italy, for genetic and technological variability. By PCR amplification with M13 primer a significant polymorphism was recorded and 12 different biotypes were identified among the strains. The specific strain-pattern could be used to follow the dynamics of different biotypes during the fermentation process. The analysis of experimental wines obtained by inoculated fermentations with the 80 strains showed significant differences among the wines. The level of each compound was a function of the strain performing the fermentative process. The main variables for the strain differentiation were the production of acetaldehyde and acetic acid, which ranged from 53 to 282 mg/l and from 0.20 to 1.88 g/l, respectively. Selected strains were tested in fermentation with two different grape musts, yielding experimental wines differing in the levels of secondary compounds and polyphenol content, in function of the interaction “grape must composition/yeast strain”. This finding has an applicative value for the potentiality of utilizing the resource of strain variability as a tool to individuate suitable starter cultures, which are able to complement and optimize grape quality.

A bacterial strain 1-1 capable of utilizing carbendazim was isolated from carbendazim-treated Qiyang red soils Hunan Province, China. It is gram-negative, rod-shaped, motile with peritrichous flagella, which formed round, smooth, convex and transparent colonies of about 1.1 mm diameter after 3 days of incubation on the isolation and purification medium using carbendazim as the sole carbon and energy sources. The degradation ratios of carbendazim by strain 1-1 were 19.16 and 95.96 in the carbendazim (500 mg/l)-degrading medium and the carbendazim (500 mg/l)-degrading medium supplemented with yeast extract (150 mg/l) within 24 days, respectively. Strain 1-1 was identified as Ralstonia sp. (β-Proteobacteria) based on the results of phenotypic features, G+C mol and phylogenetic analysis of 16S rDNA. Strain 1-1 could become a new bacterial resource for biodegrading carbendazim and might play a bioremediation role for soils contaminated by carbendazim.

Các chế phẩm giống lỏng thương mại cho đậu nành, được lưu trữ ở 20 °C trong 1–8 năm trong chai 400 ml hoặc trong bình 5000 ml, đã được đánh giá về hiệu quả và những thay đổi trong hoạt động sinh lý của Bradyrhizobium japonicum. Một sự giảm sút trong số lượng vi khuẩn sống sót và trong khả năng sống sót của vi khuẩn trên hạt giống đã được quan sát thấy ở các chế phẩm giống lưu trữ trong nhiều năm. Số lượng nốt sản xuất trên mỗi cây trong buồng tăng trưởng giảm xuống và có tương quan với số lượng vi khuẩn còn sống sót trên hạt giống. Những thay đổi trong các đặc tính sinh lý đã được đánh giá bằng các phương pháp sinh hóa, sinh lý và vi phẫu. Nội dung đường tổng số trong tế bào giảm khi thời gian lưu trữ của chế phẩm giống tăng lên. Tỉ lệ cao tính toán của chất rắn lơ lửng khô/cacbon/đạm/protein trên mỗi c.f.u. mạnh mẽ gợi ý sự hiện diện của các tế bào chết hoặc tế bào sống nhưng không thể nuôi cấy (VBNC) trong các chế phẩm giống. Điều này đã được xác nhận trong một nghiên cứu về hoạt động hô hấp của vi khuẩn, sử dụng sự khử p-iodonitrotetrazolium. Thời gian xuất hiện của các thuộc địa trên đĩa tăng lên ở các chế phẩm giống cũ lưu trữ lâu, đặc biệt trên môi trường nuôi cấy không có nấm men. Sự không đồng nhất trong kích thước thuộc địa cũng tăng lên với thời gian lưu trữ. Các chế phẩm giống được lưu trữ lâu hơn 2 năm có thể được phân biệt với các chế phẩm khác bằng việc sử dụng acid nalidixic chống lại sự phân chia tế bào. Việc nhuộm axit nucleic trên tế bào cho thấy rằng tỷ lệ vi khuẩn bị tổn thương màng trong tất cả các chế phẩm giống tăng lên theo thời gian lưu trữ, bất kể loại bao bì được sử dụng cho các chế phẩm giống. Những kết quả này chứng minh rằng hoạt động sinh lý của tế bào B. japonicum trong các chế phẩm giống lỏng thương mại thay đổi sau khi lưu trữ. Để hoàn thiện xác định c.f.u., ba phương pháp đã được đề xuất để đánh giá sự thích nghi của bradyrhizobia lưu trữ, nhưng chúng vẫn cần được kiểm tra độ tin cậy trên đa dạng các chế phẩm giống thương mại.

Fungal morphogenesis is a regulated series of events, leading to changes from one state to another, in which proteolysis could be regarded as one of the controlling functions. Proteinases are essential for the supply of amino acids, selective inactivation of specific growth phase proteins not required during development and for the activation and modification of the enzymes involved in cell wall synthesis. A critical evaluation of the role of proteinases as a biochemical correlate in fungal morphogenesis is discussed.