Bio: Olga Meerovskaya is an academic researcher. The author has contributed to research in topics: Food additive & Bioenergy. The author has an hindex of 2, co-authored 2 publications receiving 20 citations.
06 Sep 2017
Abstract: Lactic acid bacteria (LAB) are one of the most well-studied bacterial groups known from ancient times. These valuable microorganisms are used in numerous areas, especially food industry and medicine. LAB produce a wide range of compounds for food upgrading. Moreover, LAB can find special applications like generation of bioenergy not affecting the surrounding environment. The article considers physiological and biochemical processes determining valuable characteristics of the bacteria, potential applications of LAB and their products, especially in food industry and bioenergy sector, and discusses LAB potential contribution into solution of waste disposal problem.
05 Nov 2018
TL;DR: In this paper, a review of the most important learnings from fermentation of solid biowastes to lactic acid (LA) is presented, providing an overview of the process steps while highlighting some of the current limitations to overcome.
Abstract: Solid biowastes (SBW) are organic residues from gardens and parks, food wastes from kitchens, organic municipal solid wastes and comparable side streams from food processing plants. Without proper treatment, SBW represent an environmental hazard. Several initiatives around the world are dedicated to developing more effective systems for the treatment of this constantly growing ‘resource’. The chemical composition of SBW, rich in carbohydrates, proteins and lipids, makes it a good substrate to produce biobased materials through fermentation. Amongst them, lactic acid (LA), considered one of the top ten green molecules of the future, has attracted huge interest because of its many uses as an intermediate chemical. This review gathers the most important learnings from fermentation of SBW to LA, providing an overview of the process steps while highlighting some of the current limitations to overcome. Despite their complexity, results suggest that some of the SBW could be good substrates in LA fermentations and that biosynthesis of LA should be regarded as part of the whole waste management solution.
01 Apr 2009
TL;DR: A recombinant mannose-6-phosphate isomerase from Geobacillus thermodenitrificans (GTMpi) isomerizes aldose substrates possessing hydroxyl groups oriented in the same direction at the C2 and C3 positions as discussed by the authors.
Abstract: A recombinant mannose-6-phosphate isomerase from Geobacillus thermodenitrificans (GTMpi) isomerizes aldose substrates possessing hydroxyl groups oriented in the same direction at the C2 and C3 positions such as the d- and l-forms of ribose, lyxose, talose, mannose, and allose. The activity of GTMpi for d-lyxose isomerization was optimal at pH 7.0, 70°C and 1 mM Co2+. Under these conditions, the kcat and Km values were 74,300 s−1 and 390 mM for d-lyxose and 28,800 s−1 and 470 mM for l-ribose, respectively. The half-lives of the enzyme at 60, 65, and 70°C were 388, 73, and 27 h, respectively. GTMpi catalyzed the conversion of d-lyxose to d-xylulose with a 38% conversion yield after 3 h, and converted l-ribose to l-ribulose with a 29% conversion yield.
TL;DR: In this paper, the growth stimulation potential of fermented brown juice on plumed cockscomb (Celosia argantea var. plumose ‘Arrabona’) plants were tested.
Abstract: Brown juice is a byproduct of fractionated green biomass during leaf protein isolation. It represents approximately 45%–50% of the total pressed fresh biomass. Disposal of brown juice is a serious issue in leaf protein production due to its high biological oxygen demand and carbohydrates content. The current study aimed to find a possible potential use of brown juice. Therefore, chemical and biochemical properties of brown juice—derived from alfalfa green biomass—were determined before and after fermentation by lactic acid bacteria. Additionally, the growth stimulation potential of fermented brown juice on plumed cockscomb (Celosia argantea var. plumose ‘Arrabona’) plants were tested. Celosia seedlings were sprayed at different rates of fermented brown juice (i.e., 0.5%, 1%, 2.5%, 5%, and 10%) and tap water was applied as control. The results revealed that lactic acid bacteria successfully enhanced the stabilization of brown juice via reducing sugars content and increasing organic acids content. After fermentation, contents of glucose monomers were 15 times lower; while concentrations of lactic and acetic acids increased by 7- and 10-fold, respectively. This caused a reduction in the pH of fermented brown juice by 13.9%. Treating Celosia plants at lower rates of fermented brown juice (up to 1.0%) significantly induced their growth dynamics and antioxidant capacity. Higher values of vegetative parameters were measured in treated plants compared to control. The brown juice treatments caused significant changes in histological parameters as well. The activity of catalase and peroxidase increased in plants that received fermented brown juice especially at low rates. Moreover, an increase in water-soluble protein and phenol was measured in different tissues of plants sprayed with fermented brown juice. Malondialdehyde content was lowered in treated plants compared to control. Fermented brown juice at high rates slightly reduced the amount of photosynthetic pigments; however, this reduction was not reported for low rates of fermented brown juice. These results surely illustrate the potential use of fermented alfalfa brown juice as a growth stimulator for crops particularly at rates below 2.5%.
TL;DR: Some characteristics of the Geobacillus species found in the oilfield environment are summarized, focusing on the inference and analysis of hydrocarbon degradation and bioemulsifier synthesis based on existing research, which may reveal their potential value in microbial enhanced oil recovery.
Abstract: Bacteria from the genus Geobacillus are generally obligately thermophilic, with a unique bioenergy production capacity and unique enzymes. Geobacillus species were isolated primarily from hot springs, oilfields, and associated soils. They often exhibit unique survival patterns in these extreme oligotrophic environments. With the development of the microbial resources found in oilfields, Geobacillus spp. have been proven as valuable bacteria in many reports related to oilfields. After the isolation of Geobacillus by culture methods, more evidence was found that they possess the abilities of hydrocarbon utilization and bioemulsifier production. This paper mainly summarizes some characteristics of the Geobacillus species found in the oilfield environment, focusing on the inference and analysis of hydrocarbon degradation and bioemulsifier synthesis based on existing research, which may reveal their potential value in microbial enhanced oil recovery. It also provides references for understanding microbes in extreme environments.