Enzyme preparation with hydrolytic action to intensify the fermentation process

В работе представлены результаты исследований ферментного препарата гидролитического действия, обладающего инвертазной активностью, синтезируемого промышленным штаммом Aspergillus niger Л-4 - продуцентом лимонной кислоты, - в условиях глубинной ферментации гидролизата кукурузного крахмала, в технологии хлебопечения с целью интенсификации процесса брожения. The paper presents the results of studies of the effect of an enzyme preparation of hydrolytic action with invertase activity, synthesized by the industrial strain Aspergillus niger L-4, a citric acid producer under conditions of deep fermentation of starch hydrolyzate, in baking technology in order to intensify the fermentation process.

Draft Genome Sequence of Saccharomyces cerevisiae Strain Awamori Number 101, Commonly Used to Make Awamori, a Traditional Spirit, in Okinawa, Japan

We report here the draft genome sequence for Saccharomyces cerevisiae strain Awamori number 101, an industrial strain used for producing awamori, a distilled alcohol beverage. It was constructed by assembling the short reads obtained by next-generation sequencing. The 315 contigs constitute an 11.5-Mbp genome sequence coding 6,185 predicted proteins.

Saccharomyces Cerevisiae Strains Selected from Nature Significantly Increased the Production of 2-Phenylethanol Through Protoplast Fusion

Background: 2-Phenylethanol (2-PE) is an aromatic alcohol with rose fragrance, which is widely used as an additive in food, tobacco and daily chemical industries. Yeast is the main microorganism producing natural 2-PE, but it is limited by low production and weak tolerance. Nature and fermented products is a resource treasury of yeasts with excellent traits. Screening strains with good phenotypic traits and conducting breeding by cell fusion for genetic pyramiding is an effective way to improve strains. Results: In this study, 25 strains of 2-PE-producing yeasts were isolated from Chinese brewed samples. Three Saccharomyces cerevisiae strains with good traits in tolerance and 2-PE titre were screened out. The strain LSC-1 produces 2-PE of 3.41 g/L with an increase of 9.3% compared to the industrial strain CWY132. The strain NGER shows good tolerance to 2-PE at the concentration of 3.60 g/L in agar plate, and the thermotolerant strain S.C-1 shows growth ability at 41℃. Two rounds of protoplast fusion were performed with these three parent strains for pyramiding of traits. A fusant strain RH2-16 with high 2-PE titre and increased tolerance was obtained. Using 5g/L L-phenylalanine as the precursor substrate, the maximum titre of 2-PE produced by the RH2-16 strain through fermentation and transformation is 4.31 g/L, and the average titre is 4.04 g/L. The molar conversion rate of L-Phe reached 115% in 36 h. Compared to the parental strain LSC-1 and the industrial strain CWY132, 2-PE titre in RH2-16 increased by 26.4% and 38.1%, respectively.Conclusion: Diversified S. cerevisiae strains with different traits can be isolated from the brewing related samples. Protoplast fusion technology can effectively pyramid excellent genetic traits and breed yeast strains with significantly improved tolerance and 2-PE titre. Our research provided a breeding strategy for S. cerevisiae and a strain for industrial production of 2-PE.

Saccharomyces Cerevisiae Strains Selected From Nature Significantly Increased the Production of 2-Phenylethanol Through Protoplast Fusion

Background: 2-Phenylethanol (2-PE) is an aromatic alcohol with rose fragrance, which is widely used as an additive in food, tobacco and daily chemical industries. Yeast is the main microorganism producing natural 2-PE, but it is limited by low yield and weak tolerance. Nature and fermented products is a resource treasury of yeasts with excellent traits. Screening strains with good phenotypic traits and conducting breeding by cell fusion for genetic pyramiding is an effective way to improve strains. Results: In this study, 25 strains of 2-PE-producing yeasts were isolated from Chinese brewed samples. Three Saccharomyces cerevisiae strains with good traits in tolerance and 2-PE yield were screened out. The strain LSC-1 produces 2-PE of 3.41 g/L with an increase of 9.3% compared to the industrial strain CWY132. The strain NGER shows good tolerance to 2-PE at the concentration of 3.60 g/L in agar plate, and the thermotolerant strain S.C-1 shows growth ability at 41℃. Two rounds of protoplast fusion were performed with these three parent strains for pyramiding of traits. A fusion strain RH2-16 with high 2-PE yield and increased tolerance was obtained. Using 5 g/L L-phenylalanine as the precursor, RH2-16 produced 2-PE of 4.31 g/L through fermentation conversion and the molar conversion rate of L-Phe reached 115% in 36 h. Compared to the yield of the parental strain LSC-1 and the industrial strain CWY132, 2-PE in RH2-16 increased by 26.4% and 38.1%, respectively. Overexpression of the key enzyme genes ARO8, ARO10, and ADH2 in the Ehrlich pathway in RH2-16 did not increase 2-PE production.Conclusion: Diversified S.cerevisiae strains with different traits can be isolated from the brewing related samples. Protoplast fusion technology can effectively pyramid excellent genetic traits and breed yeast strains with significantly improved tolerance and 2-PE yield. Our research provided a breeding strategy for S.cerevisiae and a strain for industrial production of 2-PE. Overexpression of the key enzyme genes in 2-PE synthesis pathway does not necessarily improve increase production.

Biocontrol Using Bacillus amyloliquefaciens PP19 Against Litchi Downy Blight Caused by Peronophythora litchii

Bacillus amyloliquefaciens has been widely used in the agriculture, food, and medicine industries. Isolate PP19 was obtained from the litchi fruit carposphere and showed biocontrol efficacy against litchi downy blight (LDB) whether applied preharvest or postharvest. To further understand the underlying regulatory mechanisms, the genome of PP19 was sequenced and analyzed. The genome comprised a 3,847,565 bp circular chromosome containing 3990 protein-coding genes and 121 RNA genes. It has the smallest genome among 36 sequenced strains of B. amyloliquefaciens except for RD7-7. In whole genome phylogenetic analysis, PP19 was clustered into a group with known industrial applications, indicating that it may also produce high-yield metabolites that have yet to be identified. A large chromosome structural variation and large numbers of single nucleotide polymorphisms (SNPs) between PP19 (industrial strain) and UMAF6639 (plant-associated strain) were detected through comparative analysis, which may shed light on their functional differences. Preharvest treatment with PP19 enhanced resistance to LDB, by decreasing the plant H2O2 content and increasing the SOD activity. This is the first report of an industrial strain of B. amyloliquefaciens showing a plant-associated function and with major potential for the biocontrol of LDB.

SYMBIOTIC ACTIVITY OF MEDICAGO VARIA MART. DEPENDING ON THE TYPE OF NITROGEN NUTRITION

The issue of the use of mineral forms of nitrogen for legumes is still a source of debate among scientists. Under the environmental conditions of the foothill zone of RNO-Alania, the field experiments were laid to study the activity of the symbiotic system and the productivity of the alfalfa depending on the type of nitrogen nutrition and the presence of a virulent active strain of rhizobia. The research was carried out in 2017– 2019. Soil – chernozems leached. Objects: crops of Medicago varia Mart.; industrial strain of rhizotorphin 425a; inoculum of high-mountain strains of nodule bacteria; starting doses of nitrogen fertilizers. The dimensions of the symbiotic apparatus were studied according to the G.S. Posypanov method. The specific activity of symbiosis was 4.2 to 9.0 mg/kg. The maximum amount of air nitrogen (456.1 kg/ha) for three years of experiments was fixed by the symbiotic system of alfalfa in the variant with pre-sowing seed inoculation with high-mountain strains of nodule bacteria. This indicates their higher activity and competitiveness compared to the industrial strain of rhizotorphin 425a and indigenous strains of rhizobia from the pre-mountain zone of RNO-Alania. Mineral forms of nitrogen significantly inhibited the activity of the symbiotic system. As a result, the amount of fixed nitrogen decreased by 3.5–9.0 %. In the pre-mountain zone, under natural conditions, the growth and development of plants were provided with atmospheric nitrogen by 66 %, the rest of the need for the element (34 %) they satisfied with soil nitrogen. The maximum involvement of molecular nitrogen of the atmosphere in the biological cycle was distinguished by the variant with pre-sowing inoculation of seeds by virulent active strains of rhizobia, in which the share of air nitrogen participation in plant nutrition averaged 71–73 % over the three years of research.