scholarly journals Control tools to selectively produce purple bacteria for microbial protein in raceway reactors

Author(s):  
Abbas Alloul ◽  
Marta Cerruti ◽  
Damian Adamczyk ◽  
David G. Weissbrodt ◽  
Siegfried E. Vlaeminck

AbstractPurple non-sulfur bacteria (PNSB) show potential for microbial protein production on wastewater as animal feed. They offer good selectivity (i.e. uneven community with high abundance of one species) when grown anaerobically in the light. However, the cost of a closed anaerobic photobioreactor (PBR) is prohibitive for protein production. While open raceway reactors are cheaper, their feasibility to selectively grow PNSB is thus far unexplored. This study developed tools to boost PNSB abundance in the biomass of a raceway reactor fed with volatile fatty acids as carbon source. For oxygen availability as tool, not stirring in the night (i.e. reduced oxygen supply) elevated the PNSB abundance from 8% to 20%. For light availability as tool, a 24-h illumination increased the PNSB abundance from 8% to 31% compared to a 12-h light/12-h dark regime. A reactor run at 2-d sludge retention time at the highest surface-to-volume ratio (10 m2 m-3 increased light availability) showed productivities up to 0.2 g protein L-1 d-1 and the highest PNSB abundance (78%). The estimated production cost is €1.9 kg-1 dry weight (vs. PBR €11.4 kg-1 dry weight). This study pioneered in PNSB-based microbial protein production in raceways, yielding cost efficiency along with high selectivity when avoiding the combined availability of oxygen, COD and darkness.Graphical abstract

1970 ◽  
Vol 21 (2) ◽  
pp. 305 ◽  
Author(s):  
ID Hume

Protein production in the rumen of sheep fed on a virtually protein-free diet supplemented with urea and higher volatile fatty acids (VFA) and yielding 600 g digestible organic matter per day amounted to 90 g/day. When gelatin was substituted for the higher VFA and 50% of the urea nitrogen, microbial protein production remained at a similar level (91 g/day); with casein, production increased to 101 g/day, and with zein to 104 g/day. Nitrogen balances increased from 4.1 g/day in sheep fed on the casein diet to 5.5 g/day in those fed on the zein diet (P < 0.05). These values were both significantly higher than those for the urea/VFA or gelatin-containing diets, reflecting the different levels of microbial protein production on the respective diets. In addition, 44 g un-degraded zein left the rumen daily, accounting for the increase in nitrogen balance on this diet above that on the casein diet. Negligible amounts of nitrogen were recycled on the urea/VFA, gelatin, and casein treatments, but at least 7.5 g recycled nitrogen was utilized in the rumen daily on the zein diet. This is equivalent to 47 g protein, sufficient in itself to satisfy the maintenance requirement of the sheep for protein. The yields of protein from ruminal fermentation on the three protein treatments suggest that the maximum possible yield may exceed 20 g/100 g organic matter digested in the rumen.


1985 ◽  
Vol 17 (4-5) ◽  
pp. 803-817 ◽  
Author(s):  
Gideon Oron ◽  
Louw R. Wildschut ◽  
Dan Porath

Waste water treatment and recycling facilities are becoming increasingly necessary in arid zones, especially in the light of the shortage of conventional water sources. The simultaneous treatment of waste water and the production of duckweed in a pond system, as an alternative protein source, is an attractive proposition for solving the feed and water shortage problem. Outdoor experiments conducted in mini-ponds showed that duckweed ponds may be highly competitive with existing secondary treatment methods. The duckweed biomass, with a crude protein content of above 30% (dry weight), may be used as an alternative source for animal feed. The ease of the duckweed harvesting makes the system even more economically attractive. The work describes the basic outdoor biotechnology aimed at eliminating the superior organic loading in the pond as given by the ratio of COD and NH+4 in the raw domestic sewage. This ratio was examined in respect to the retention time of the wastes in the ponds and protein production by the floating vascular plant biomass.


2021 ◽  
Vol 21 (2) ◽  
pp. 192-199
Author(s):  
Limbang Kustiawan Nuswantara ◽  
Eko Pangestu ◽  
Sunarso Sunarso ◽  
Marry Christiyanto

ABSTRACT. Penelitian bertujuan mengetahui kualitas complete feed dengan level pelepah sawit fermentasi berdasarkan kecernaan bahan kering, bahan organik, produksi N-NH3, produksi volatile fatty acids (VFA) dan produksi biomassa protein mikrobia serta protein total secara in vitro. Materi yang digunakan adalah complete feed tersusun atas konsentrat dan pelepah sawit fermentasi dengan berbagai level yaitu 0, 10, 20 dan 30%. Rancangan percobaan yang digunakan adalah rancangan acak lengkap (RAL) dengan 4 perlakuan complete feed dengan level pelepah sawit fermentasi yang berbeda. Data diolah menggunakan sidik ragam yang dilanjutkan dengan uji beda wilayah berganda Duncan. Hasil penelitian menunjukkan bahwa complete feed dengan level pelepah sawit fermentasi yang berbeda berpengaruh nyata (p0,05) terhadap kecernaan bahan kering dan bahan organik, produksi N-NH3, produksi VFA, dan produksi protein total, sedangkan pada biomassa protein mikrobia tidak terdapat perbedaan yang nyata (p0,05). Rata-rata nilai kecernaan bahan kering pada perlakuan T0, T1, T2 dan T3 adalah 69,59; 71,9; 69,05; dan 62,58%. Rata-rata nilai kecernaan bahan organik pada perlakuan T0, T1, T2 dan T3 adalah 63,59; 63,15; 65,50; 52,66 %. Rata-rata produksi VFA pada perlakuan T0, T1, T2 dan T3 sebesar 105,8; 142,7; 136,4; dan 135,7 mM. Rata-rata produksi NH3, biomassa protein mikrobia dan produksi protein total pada perlakuan T0, T1, T2 dan T3 berturut-turut adalah 6,48mM, 15,04mg/ml;, 34,10mg/g; 7,36mM, 15,75mg/ml, 23,72mg/g; 8,18mM, 12,59mg/ml, 33,72mg/g); dan 6,60mM, 15,31mg/ml, 40,80mg/g. Berdasarkan hasil penelitian disimpulkan bahwa penggunaan pelepah sawit fermentasi dengan level 20% dalam complete feed menghasilkan produksi VFA, kecernaan bahan kering dan bahan organik yang cukup baik sehingga dapat menjadi pakan alternatif sumber serat pengganti rumput. (Digestibility, fermentability and in-vitro production of microbial protein on complete feed based on fermented palm frond) ABSTRAK. This study aimed to determine the quality of a complete feed containing fermented palm fronds based on the digestibility of dry matter, organic matter, N-NH3, VFA, microbial protein biomass, and total protein in vitro. The material used was complete feed composed of concentrates and fermented palm fronds at various levels, i.e., 0, 10, 20, and 30%. The experiment was conducted as a completely randomized design (CRD) with four complete feed treatments containing different levels of fermented palm fronds. The data were processed using analysis of variance, followed by Duncan’s multiple range test. The results demonstrated that the complete feed with different levels of fermented palm fronds had a significant effect (p0.05) on the digestibility of dry matter and organic matter, N-NH3 production, essential fatty acids production, and total protein production, whereas there was no significant difference (p 0.05) on microbial protein biomass. The average dry matter and organic matter digestibility values of T0, T1, T2, and T3 treatments were 69.59; 63.59, 71.9; 63.15, 69.05; 65.50, and 62.58%; 52.66% respectively. The average production of volatile fatty acids of T0, T1, T2, and T3 treatments were 105.8; 142.7; 136.4; and 135.7 mM. respectively, while the average N-NH3 production, microbial protein biomass, and total protein production of the T0, T1, T2, and T3 treatments were 6.48, 7.36, 8.18, 6.60 mM; 15.04, 75, 12.59, 15.31 mg/ml; and 34.10, 23.72, 33.72, 40.80 mg/g. In conclusion, the use of fermented palm fronds at a 20% level in complete feed gave the best result in the production of volatile fatty acids, improved digestibility of dry matter, and organic matter, so it can be used as an alternative feed to replace grass fiber.


1970 ◽  
Vol 21 (2) ◽  
pp. 297 ◽  
Author(s):  
ID Hume

When sheep were fed on a virtually protein-free purified diet adequately supplied with nonprotein nitrogen, 71 g microbial protein was produced in the rumen daily. The addition of a mixture of higher volatile fatty acids (VFA) increased protein production to 81 g daily (P < 0.05). The VFA supplement also increased the molar proportions of these acids in the rumen fluid and the flow of total nitrogen from the rumen. There were no differences in nitrogen balance associated with the supplement. There were significant variations between sheep and between periods in both protein production and the molar proportion of acetic acid in the rumen fluid. A negative correlation was found between acetic acid proportions and protein production (r = -0.62, P < 0.025). The mean yield of protein from the ruminal fermentation was 13.0 g/100 g organic matter digested in the rumen. The addition of the higher VFA did not result in any appreciable increase in the efficiency of protein production from the energy available.


2015 ◽  
Vol 55 (1) ◽  
pp. 17 ◽  
Author(s):  
D. V. Tuyen ◽  
X. M. Tolosa ◽  
D. P. Poppi ◽  
S. R. McLennan

The present experiment was conducted to determine the efficiency of microbial protein production in the rumen and intake by cattle fed high-molasses diets. Intake and microbial crude protein (MCP) production were measured along with the concentration of rumen ammonia-nitrogen (N) and volatile fatty acids (VFA), pH and the rate of digestion of roughage in the rumen. Eight Brahman crossbred steers weighing 211 ± 19.3 (± s.d.) kg were used in a double 4 × 4 Latin square design. Steers were allocated to one of four total mixed rations: control (pangola hay only), 25M (25% molasses/urea mix + 75% hay), 50M (50% molasses/urea + 50% hay), and 75M (75% molasses/urea + 25% hay). The production and efficiency of production of MCP (EMCP) of the diet increased quadratically as the level of molasses in the diet increased. The EMCP from the molasses/urea mix was estimated as 166 g MCP/kg digestible organic matter (DOM), a relatively high value. Intake of dry matter (DM) and DOM increased quadratically, reaching a peak when molasses was ~50% (as fed) of the ration. Digestibility of DM increased quadratically and that of neutral detergent fibre decreased linearly with increasing level of molasses in the diet. Molasses inclusion in the diet had no effect on rumen pH, ammonia and VFA concentration in the rumen fluid, plasma urea-N, urine pH or ruminal fractional outflow rate of ytterbium-labelled particles and Cr-EDTA. It was concluded that a diet with a high level of molasses (>50%) and supplemented with adequate N had high EMCP, and that low MCP production was not a factor limiting intake or performance of cattle consuming high-molasses diets.


Author(s):  
Abbas Alloul ◽  
Marta Cerruti ◽  
Damian Adamczyk ◽  
David G. Weissbrodt ◽  
Siegfried E. Vlaeminck

1975 ◽  
Vol 85 (1) ◽  
pp. 93-101 ◽  
Author(s):  
D. G. Harrison ◽  
D. E. Beever ◽  
D. J. Thomson ◽  
D. F. Osbourn

SUMMARYThe effects of an altered rumen dilution rate (D) upon the molar proportions of volatile fatty acids (VFA) in rumen liquor, VFA production rate, microbial protein synthesis and carbohydrate digestion within the rumen were studied using adult wether sheep.Dilution rate and VFA proportions were unaltered by the infusion of up to 121 water/day into the rumen of sheep fed dried grass and concentrate (9:1). There was a small but significant (P< 0·05) increase in the rumen volume when the infusion rate was increased from 8 to 12 1/day.The intraruminal infusion of artificial saliva (41/day), or artificial saliva containing 4% or 8% w/v polyethylene glycol (PEG) caused a significant increase in D with an associated decline in the molar proportion of propionate (Pr) in the rumen liquor. A similar effect was obtained with the intraruminal infusion of 2·5% w/v sodium bicarbonate. The overall regression of Pr on D was highly significant: Pr = 32·5–82·1D;r= –0·99, P < 0·001.A diet of flaked maize: dried grass (6:4) was offered to three sheep each fitted with a rumen cannula and with a re-entrant cannula at the proximal duodenum. The intraruminal infusion (4 1/day) of artificial saliva containing 4% w/v PEG caused a significant (P< 0·01) increase in D and a significant (P< 0·01) depression in Pr in two animals. The dilution rate and Pr in the third animal were virtually unaltered by infusion. The regression of Pr on D for the three animals was highly significant: Pr = 34·8–136·8D; r = –0·98, P < 0·001. Each increase in D was associated with an increased flow of α-linked glucose polymer, total amino acids and total microbial amino acids into the small intestine and with an increased efficiency of microbial protein synthesis within the rumen.


2021 ◽  
pp. 125723
Author(s):  
Ramanujam Srinivasan Vethathirri ◽  
Ezequiel Santillan ◽  
Stefan Wuertz

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