Peat Hydrolysates Research Articles

Peat peloids from the Bichevskoye deposits of the Khabarovsk region and their physicochemical characteristics

The authors present information about the resources of sulfide silt peloids at the Bichevskoye peat field of the Khabarovsk region. Their physicochemical properties, the fragmentary carbon composition of the liquid and concentrated peat phases, as well as the elemental composition of the organic compounds present in peat hydrolysates are described. The results of high-tech investigations confirm the presence of biologically active humic substances in the peat.

Simultaneous production of pullulan and biosorption of metals by Aureobasidium pullulans strain CH-1 on peat hydrolysate

It was demonstrated that during the growth of Aureobasidium pullulans strain CH-1 on the acid hydrolysate of peat from the Vlasina Lake, the content of metals (Cu, Fe, Zn, Mn, Pb, Cd, Ni and Cr) decreased due to biosorption. The reduction in the metal content was found to be in the range (%): 38.2–62.2, 67.7–97.3, 0.02–62.05, 0.05–23.97, 0.16–4.24, 3.45–51.72, 1.18–35.82, 0.86–44.44, for Cu, Fe, Zn, Mn, Pb, Cd, Ni and Cr, respectively. During this process, the metals were accumulated in the biomass, while pullulan, an extracellular polysaccharide produced by Aureobasidium pullulans strain CH-1, was found not to bind the above-mentioned metals.

Mathematical model forPhaffia rhodozyma growth using peat hydrolysates as substrate

The potential of peat hydrolysates for the production of astaxanthin from Phaffia rhodozyma yeast biomass in continuous fermentation was studied. Chemostat fermentations of the yeast were performed using peat hydrolysates as substrate. Kinetic parameters were calculated for the growth of the yeast and the biomass productivity was determined using mathematical models. A low maximum specific growth rate (μ max = 0.08 h -1 ) and a high Monod constant (K s = 26.2 x 10 3 ) were obtained for this substrate. The low maintenance energy requirement found, 0020 g (gh) -1 , confirms the aerobic metabolism of the yeast with this substrate. Under selected conditions, a biomass productivity of 0.108 g (1h) -1 and an astaxanthin productivity of 0.046 mg (1h) -1 were obtained. The biomass produced had a high protein and astaxanthin content (490 ± 8 g kg -1 and 0.43 ± 0.07 g kg -1 , respectively), indicating that it can be used as a feed additive.

Utilization of molasses for biosurfactant production by two Bacillus strains at thermophilic conditions

AbstractTraditionally, biosurfactants have been produced from hydrocarbons. Some possible substitutes for microbial growth and biosurfactant production include urban wastes, peat hydrolysate, and agro‐industrial by‐products. Molasses, a nonconventional substrate (agro‐industrial by‐product) can also be used for biosurfactant production. It has been utilized by two strains of Bacillus subtilis (MTCC 2423 and MTCC1427) for biosurfactant production and growth at 45°C. As a result of biosurfactant accumulation, the surface tension of the medium was lowered to 29 and 31 dynes/cm by the two strains, respectively. This is the first report of biosurfactant production by strains of B. subtilis at 45°C. Potential application of the biosurfactant in microbial enhanced oil recovery is also presented.

HPLC separation and subsequent detection of aromatic heptaene polyenes in peat after treatment with Streptomyces griseoviridis

AbstractAromatic heptaene polyenes (AHPs), the largest group of antifungal polyene antibiotics, were detected in steam‐sterilized Sphagnum peat after treatment with a new biofungicide containing fermenter‐cultivated Streptomyces griseoviridis Anderson K61, a bacterium capable of producing AHPs in vitro. Three concentrations (0.05 g litre−1, 0‐2 g litre−1 and 2.0 g litre−1) of the biofungicide were used and compared to untreated controls. The substrates were incubated for seven weeks under greenhouse conditions, with and without cucumber seedlings, and samples were analysed for heptaene polyenes by HPLC using a photodiode array detector. Changes in AHP concentrations indicated that the fermenter‐cultivated mycelium was a partial source of extractable heptaenes in peat. The identification of p‐aminoacetophenone (PAAP) by HPLC‐MS in peat hydrolysates verified the presence of AHPs.

Growth kinetics of Rhodotorula rubra on different substrates

AbstractThe growth of a red‐pigmented yeast, isolated from yogurt and identified as Rhodotorula rubra, was studied on various industrial and agricultural by‐products. Peat hydrolysate when supplemented with peptone and yeast extract supported a satisfactory growth of the yeast. Ammonium hydroxide and ammonium sulfate were the best inorganic nitrogen sources. A yield of 11.8 g/1 was obtained on molasses and wort used in a concentration of 10 and 40% (v/v), respectively. Molasses were pre‐treated to be effective. The best yield of 14 g/1, however, was obtained on a richer medium composed of molasses, peptone and yeast extract. The pH profiles were also studied and growth was found within a broad pH zone of 3–10.

Study of Growth Parameters for Phaffia rhodozyma Cultivated in Peat Hydrolysates

The yeastPhaffia rhodozyma, known for its ability to synthesize carotenoids, was adapted and cultivated in liquid-phase media using peat hydrolysates as the main substrate source. The hydrolysates were prepared using high-pressure treatment at 185°C, without the addition of acid. The growth of the yeast was studied as a function of the pH, temperature, culture time, and agitation speed. The best conditions for the growth of the yeast were: a pH of 7, a temperature of 18°C, 5-d culture time, and 200-rpm agitation. Under those conditions, P.rhodozyma produced a concentration of 1279.82 μg carotenoids g-1 dry yeast, which compares well with other previously reported results.

Assessment of acid hydrolysates of peat as substrate for Scytalidium acidophilum ATCC 26774 fungus

AbstractThe acid‐resistant fungus Scytalidium acidophilum ATCC 26774 was cultivated in submerged fermentation in hydrolysates of Sphagnum peat moss produced with H2SO4, HCl, HNO3 and H3PO4 acids. Hydrolysis with H2SO4 produced the highest concentration of total carbohydrates and reducing sugars in the hydrolysates. However, when Scytalidium acidophilum ATCC 26774 was grown in undiluted hydrolysates, the H3PO4 medium produced the best mycelial growth. The H2SO4 medium produced the highest dry biomass concentration (3.5 g dm−3) obtained with water‐diluted, non‐supplemented peat hydrolysates. Supplementation of diluted H2SO4 hydrolysates with 3 g dm−3 yeast extract and 0.4 g dm−3 MgSO4 considerably enhanced the growth, up to 5.9 g dm−3 dry fungal biomass.The biomass composition of Scytalidium acidophilum ATCC 26774 grown in the medium which produced the best growth was determined, revealing a relatively high protein content of 37.5% of the dry mycelial weight.

Fate of Contaminants during Utilization of Peat Materials

AbstractSince peat soils are used for a variety of industrial purposes, the fate of contaminants in peat is of interest for environmental impact studies. Peat soils effectively retain many contaminants and can receive contaminants from both the atmosphere and groundwater. We investigated the fate of I, Se, Cs, U, and Pb in peats subjected to treatments simulating commercial processes. The soils were contaminated with three concentrations of the study elements and incubated for 3 yr. Subsamples were subjected to static pyrolysis, extraction with base, acid hydrolysis, and extraction with chelates to represent burning of peat, humic and fulvic acid extraction as industrial materials, carbohydrate extraction for single‐cell protein production, and application of chelate‐based fertilizers. The results are presented as product concentration ratios and percent recoveries. In several cases, the contaminants were markedly concentrated. As an example, food products produced from fungal culture in peat hydrolysates may contain 50‐fold higher U concentrations, on a dry wt. basis, than the original peat. Thus, contaminants are transferred to these products and this should be considered for environmental and human safety.

Fish offal-peat compost extracts as fermentation substrate

Hydrolysates of peat-fish offal compost were used as substrate sources for the growth of the acid-tolerant fungus Scytalidium acidophilum. This fungus has been previously grown on acid peat hydrolysates, and it was expected that higher concentrations of nutrients, such as nitrogen, in the fish offal-peat compost, would enhance the fungal growth. In shake-flask experiments, culture media based on the compost hydrolysates produced 2·5 g/litre of dry fungal biomass, which was not significantly different from the concentration obtained when diluted Sphagnum peat hydrolysate was employed at the substrate source. However, it was not necessary to dilute the compost hydrolysates, as is required with the peat hydrolysates, to facilitate the growth of S. acidophilum. The potential for the compost hydrolysate to support a higher microbial growth when it is supplemented with carbohydrates is discussed.

The production of surfactin by Bacillus subtilis grown on peat hydrolysate

Horticultural grade sphagnum peat was subjected to acid hydrolysis under various conditions. The hydrolysis was accomplished with concentrations of sulphuric acid between 0.5 and 2% for either 1 or 2 h at 124°C. Six monosaccharides in the hydrolysate were identified by HPLC analysis. A maximum sugar concentration of 7.7g/l was obtained with glucose accounting for 46% of the total.

Effect of nutrient compositions in peat hydrolysate on protein and biomass yields of Candida tropicalis

Research was conducted to study the effect of nutrient compositions, at different levels, added in peat hydrolysates on biomass yields and protein of Candida tropicalis. Samples of Minnesota sphagnum peat were hydrolyzed by boiling at 100°C with 1-1 H2SO4 solutions to produce peat hydrolysates which can support the growth of yeast. Peat hydrolysates were adjusted to pH 5.5 and mixed with mineral nutrients (NH4NO3, NaH2PO4 + Na2HPO4, KCl, and MgSO4) and glucose. Among the single nutrients tested, glucose produced the most significant enhancement of biomass yields, followed by NH4NO3, NaH2PO4 + Na2HPO4, KCl, and MgSO4. NH4NO3 was found to be the most important single nutrient affecting protein accumulation in yeast cells, followed by glucose > NaH2PO4 + Na2HPO4 > KCl > MgSO4. However, protein and biomass production was significantly (P ≤ 0.05) greater for combined nutrients than for any single-nutrient enrichment. The level of residual reducing sugars in peat hydrolysate was inversely proportional to cell counts and optical densities. Addition of high concentrations of nutrients delayed the time of reaching to stationary phase in optical density, cell counts, and pH of yeast cultures. In general, as nutrients were increased, significant (P ≤ 0.05) increases in productivity and cell density were observed. However, specific growth rate decreased with increasing nutrient concentrations. It was concluded that nutrient amendments containing supplementary sources of C/N/P/K/S = 400:36:3.3:3.8:1 are most suitable for biomass production and the biosynthesis of protein by C. tropicalis.

A REVIEW of FUNDAMENTAL PROCESS ASPECTS FOR the PRODUCTION of MUSHROOM MYCELIUM

ABSTRACTA review of fundamental process aspects to produce mushroom mycelium in submerged culture is presented. With peat hydrolysate as the main nutrient source, the operations of substrate preparation, cultivation and product recovery are explained. Based on the growth of Agaricus spp. mushroom mycelium, the conditions for the production of the desired mycelial pellets are analyzed.

Effects of Some Environmental Factors on Growth Characteristics of Candida utilis on Peat Hydrolysates

Samples of peat from Pine Island and Brookston bogs in Minnesota were hydrolyzed with various concentrations of HCl or H(2)SO(4) solutions, before or after debituminization (an extraction process used to remove waxy materials, bitumens, from peat), to produce peak hydrolysates as growth substrates for Candida utilis. Hydrolysates were neutralized with concentrated NaOH solution to pH 3.5, 4.5, 5.0, 5.5, 6.0, and 7.0. The precipitated humates were removed by filtration. The resulting peat hydrolysates were amended with reagent-grade K(2)HPO(4), K(2)SO(4), and MgSO(4), 200, 100, and 50 mg per liter of peat hydrolysate, respectively. The debituminized peat produced more total nitrogen (TN) and reducing substances (RS) than the nondebituminized peat. Peat hydrolysates produced by HCl solutions contained slightly higher RS and TN than those produced by H(2)SO(4) solutions; however, the latter were better growth substrates than the former. The yield coefficients in both H(2)SO(4) and HCl hydrolysates initially decreased at 12 to 24 h and then increased gradually over the remaining incubation period (24 to 96 h). As TN and RS were increased, an increase in cell density, biomass, and productivity was observed. In contrast, a decrease in specific growth rate occurred as the RS and TN were increased. The generation time of C. utilis was affected by the concentrations of RS and TN. A peak substrate yield coefficient was found at pH 5.0 in HCl hydrolysates and at pH 6.0 to 6.5 in H(2)SO(4) hydrolysates. Good linear correlation coefficients were found between RS and biomass of C. utilis. The coefficients of correlation increased as the TN level in hydrolysates was increased.

Peat Hydrolysate Medium Optimization for Pullulan Production

Peat hydrolysate, a diluted acid-autoclaved extract of peat, was used as a substrate for the production of the extracellular polysaccharide pullulan by three strains of Aureobasidium pullulans, 140B, 142, and 2552. It was found that the addition of (NH(4))(2)SO(4) and K(2)HPO(4) as sources of nitrogen and phosphate, respectively, is not necessary for the polysaccharide production. The economically optimized culture medium for large-scale production of pullulan contains peat hydrolysate, 0.05% NaCl, 0.02% MgSO(4), and 0.01% antifoam FG-10. The initial pH of peat hydrolysate medium is adjusted to its optimum value of 6.0 with Ca(OH)(2). The total ingredient cost for the production of each kilogram of pullulan with optimized medium is only 1/10 of that with the nonoptimized medium. In this study, a zero cost for peat hydrolysate was assumed, since it is an effluent of the peat and peat processing industries.

Submerged growth of Morchella esculenta in peat hydrolysates

Sphagnum peat acid hydrolysates have been successfully tested as a culture medium for the submerged growth of the fungus Morchella esculenta in batch fermentations. When glucose and (NH4)2HPO4 are added to the hydrolysate, the concentration of biomass produced is lower than that obtained from nonsupplemented hydrolysates having an equivalent total carbohydrate (TCH) content. Therefore, it appears that the concentration of some essential nutrients (s), as well as the TCH content, is affected by the conditions of hydrolysis.

A preliminary investigation on the chemical composition of sphagnum moss and peat

AbstractSphagnum, heather (Calluna vulgaris) and peat samples have been analysed for total ash, crude fats, Kjeldahl nitrogen, cellulose, total reducing substances, reducing sugars and the individual sugars glucose, galactose, arabinose and xylose. Xylose, mannose, fucose and ribose were isolated from a peat hydrolysate and characterised. Fructose and fructose‐containing oligosaccharides were found chromatographically in the fresh Sphagnum. A polysaccharide has been isolated from peat in which glucose is the principal sugar along with mannose, galactose, xylose, an unidentified uronic acid and a trace of rhamnose. The free amino‐acids of Sphagnum and peat, and the amino‐acids in the hydrolysates have been examined chromatographically. Chloroform extraction of Sphagnum gave a sterol fraction resembling ‘β’‐sitosterol.