Efficiency of lactose hydrolysis in secondary milk raw materials

Abstract BackgroundRaw materials composed of easily assimilated monosaccharides have been employed as carbon source for production of microbial lipids. Nevertheless, agro-industrial wastes rich in galactose-based carbohydrates have not been introduced as feedstocks for oleaginous yeasts. ResultsIn this study, Aureobasidium namibiae A12 was found to efficiently accumulate lipid from soy molasses and whey powder containing galactose-based carbohydrates, with lipid productions of 5.30 g/L and 5.23 g/L, respectively. Over 80% of the fatty acids was C16:0, C18:0, C18:1, and C18:2. All kinds of single sugar components in the two byproducts were readily converted into lipids, with yields ranging between 0.116 g/g and 0.138 g/g. Three α-galactosidases and five β-galactosidases in the strain were cloned and analyzed. β-galactosidase was responsible for lactose hydrolysis; sucrase and α-galactosidase both contributed to the efficient hydrolysis of raffinose and stachyose in a cooperation manner. ConclusionsThis is a new way to produce lipids from raw materials containing galactose-based carbohydrates. This finding revealed the significance of sucrase in the direct hydrolysis of galactose-based carbohydrates in raw materials for the first time and facilitated the understanding of the efficient utilization of galactose-based carbohydrates to manufacture lipid or other chemicals in bioprocess

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Whole conversion of agro-industrial wastes rich in galactose-based carbohydrates into lipid using oleaginous yeast Aureobasidium namibiae

Biotechnology for Biofuels ◽

10.1186/s13068-021-02031-8 ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

Zhi-Peng Wang ◽

Xin-Yue Zhang ◽

Yan Ma ◽

Jing-Run Ye ◽

Jing Jiang ◽

...

Keyword(s):

Oleaginous Yeast ◽

Raw Materials ◽

Lipid Production ◽

Industrial Wastes ◽

Lactose Hydrolysis ◽

Oleaginous Yeasts ◽

Soy Molasses ◽

First Time ◽

Hydrolysis Of ◽

Direct Hydrolysis

Abstract Background Raw materials composed of easily assimilated monosaccharides have been employed as carbon source for production of microbial lipids. Nevertheless, agro-industrial wastes rich in galactose-based carbohydrates have not been introduced as feedstocks for oleaginous yeasts. Results In this study, Aureobasidium namibiae A12 was found to efficiently accumulate lipid from soy molasses and whey powder containing galactose-based carbohydrates, with lipid productions of 5.30 g/L and 5.23 g/L, respectively. Over 80% of the fatty acids was C16:0, C18:0, C18:1, and C18:2. All kinds of single sugar components in the two byproducts were readily converted into lipids, with yields ranging between 0.116 g/g and 0.138 g/g. Three α-galactosidases and five β-galactosidases in the strain were cloned and analyzed. Changes of transcriptional levels indicated GalB and GalC were key α-galactosidases, and GalG was key β-galactosidase. In 10 L fermentor, lipid production from SM and WP achieved 6.45 g/L and 6.13 g/L, respectively. β-galactosidase was responsible for lactose hydrolysis; sucrase and α-galactosidase both contributed to the efficient hydrolysis of raffinose and stachyose in a cooperation manner. Conclusions This is a new way to produce lipids from raw materials containing galactose-based carbohydrates. This finding revealed the significance of sucrase in the direct hydrolysis of galactose-based carbohydrates in raw materials for the first time and facilitated the understanding of the efficient utilization of galactose-based carbohydrates to manufacture lipid or other chemicals in bioprocess. Graphic abstract

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Screening of lactases suitable for the preparation of low-lactose prebiotic liquid milk and optimisation of their combination

Acta Universitatis Cibiniensis Series E Food Technology ◽

10.2478/aucft-2021-0025 ◽

2021 ◽

Vol 25 (2) ◽

pp. 275-284

Author(s):

Yunli Xu ◽

Guowei Shu ◽

Chunji Dai ◽

Chun Yin ◽

Xu Dong ◽

...

Keyword(s):

Enzymatic Hydrolysis ◽

Dairy Products ◽

Lactose Intolerance ◽

Raw Materials ◽

Cow Milk ◽

Hydrolysis Rate ◽

Lactose Hydrolysis ◽

Enzyme Preparations ◽

Hydrolysis Process ◽

Liquid Milk

Abstract Lactose intolerance is an important factor restricting the consumption of dairy products. Lactase is used to hydrolyze lactose in milk while generating galactooligosaccharides (GOS), thereby reducing the incidence of lactose intolerance. We used cow milk as raw materials, and selected enzyme preparations with high lactose hydrolysis rate and strong GOS generation ability from 14 commercially available lactase enzymes. The lactose hydrolysis rate is 5.85%-81.38%, and the GOS content is 0.03 g/L- 13.10 g/L. The mixing experiment design determined the two lactase enzymes (E10 and E11) ratio and the optimal enzymatic hydrolysis process of low-lactose prebiotic milk: compound lactases (E10:E11=0.756:0.244) addition 0.11%, 55℃for 5h, lactose hydrolysis rate and GOS content were 98.02% and 19.69g/L, respectively, and the remaining lactose content was about 0.97 g/L.

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Microstructural characterization of laser-melted/roller-quenched dicalcium silicate

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100104972 ◽

1988 ◽

Vol 46 ◽

pp. 582-583

Author(s):

C. J. Chan ◽

K. R. Venkatachari ◽

W. M. Kriven ◽

J. F. Young

Keyword(s):

Particle Size ◽

Raw Materials ◽

Shape Change ◽

Microstructural Characterization ◽

Particle Size Effect ◽

Dicalcium Silicate ◽

Laser Melting ◽

Uniform Size ◽

Cell Shape Change ◽

Wide Range

Dicalcium silicate (Ca2SiO4) is a major component of Portland cement. It has also been investigated as a potential transformation toughener alternative to zirconia. It has five polymorphs: α, α'H, α'L, β and γ. Of interest is the β-to-γ transformation on cooling at about 490°C. This transformation, accompanied by a 12% volume increase and a 4.6° unit cell shape change, is analogous to the tetragonal-to-monoclinic transformation in zirconia. Due to the processing methods used, previous studies into the particle size effect were limited by a wide range of particle size distribution. In an attempt to obtain a more uniform size, a fast quench rate involving a laser-melting/roller-quenching technique was investigated.The laser-melting/roller-quenching experiment used precompacted bars of stoichiometric γ-Ca2SiO4 powder, which were synthesized from AR grade CaCO3 and SiO2xH2O. The raw materials were mixed by conventional ceramic processing techniques, and sintered at 1450°C. The dusted γ-Ca2SiO4 powder was uniaxially pressed into 0.4 cm x 0.4 cm x 4 cm bars under 34 MPa and cold isostatically pressed under 172 MPa. The γ-Ca2SiO4 bars were melted by a 10 KW-CO2 laser.

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Crystallization of barium hexaferrite

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100122216 ◽

1992 ◽

Vol 50 (1) ◽

pp. 362-363

Author(s):

Chung-kook Lee ◽

Yolande Berta ◽

Robert F. Speyer

Keyword(s):

Size Distribution ◽

Raw Materials ◽

Barium Hexaferrite ◽

Recording Media ◽

Magnetic Recording Media ◽

Promising Candidate ◽

Crystallization Method ◽

Temperature Heat ◽

High Density Magnetic Recording ◽

Temperature Heat Treatment

Barium hexaferrite (BaFe12O19) is a promising candidate for high density magnetic recording media due to its superior magnetic properties. For particulate recording media, nano-sized single crystalline powders with a narrow size distribution are a primary application requirement. The glass-crystallization method is preferred because of the controllability of crystallization kinetics, hence, particle size and size distribution. A disadvantage of this method is the need to melt raw materials at high temperatures with non-reactive crucibles, e.g. platinum. However, in this work, we have shown that crystal growth of barium hexaferrite occurred during low temperature heat treatment of raw batches.

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