Evaluation of thermophilic fungal consortium for paddy straw composting

Out of 10 thermophilic fungi isolated from wheat straw, farm yard manure, and soil, only three showed highest cellobiase, carboxymethyl cellulase, xylanase, and FPase activities. They were identified as Aspergillus nidulans (Th₄), Scytalidium thermophilum (Th₅), and Humicola sp. (Th₁₀). A fungal consortium of these three fungi was used to compost a mixture (1:1) of silica rich paddy straw and lignin rich soybean trash. The composting of paddy straw for 3 months, during summer period in North India, resulted in a product with C:N ratio 9.5:1, available phosphorus 0.042% and fungal biomass 6.512 mg of N-acetyl glucosamine/100 mg of compost. However, a C:N ratio of 10.2:1 and highest humus content of 3.3% was achieved with 1:1 mixture of paddy straw and soybean trash. The fungal consortium was effective in converting high silica paddy straw into nutritionally rich compost thereby leading to economical and environment friendly disposal of this crop residue.     

Effect of bioaugmentation and nitrogen supplementation on composting of paddy straw

A composting experiment was conducted to evaluate the effect of a hyperlignocellulolytic fungal consortium and different nitrogen amendments on paddy straw composting in terms of changes in physicochemical and biological parameters. A fungal consortium comprising four lignocellulolytic mesophilic fungal cultures was used as inoculum for bioaugmentation of paddy straw in perforated pits. The comparative effect of farmyard manure (FYM), soybean trash, poultry litter and urea on the composting process was evaluated at monthly intervals in terms of physicochemical (pH, EC, available P, C:N ratio and humus content) and biological (enzymatic and microbial activity) parameters. The compost prepared from bioaugmented paddy straw composting mixture, with poultry manure as nitrogen supplement attained desirable C:N ratio in 1 month and displayed least phytotoxicity levels along with higher production of β-1,4-Exoglucanase. The combined activity of the autochthonous composting microbiota as well as the externally applied fungal inoculum accelerated the composting process of paddy straw. Supplementation of paddy straw with poultry manure in 8:1 ratio was identified as the best treatment to hasten the composting process. This study highlights the importance of application of fungal inoculum and an appropriate N-amendment such as poultry manure for preparation of compost using a substrate having high C:N ratio, such as paddy straw.     

Co-composting of physic nut (Jatropha curcas) deoiled cake with rice straw and different animal dung

To address the dispensing of this growing volume, a study on utilization of jatropha (Jatropha curcas) deoiled cake through compost production was carried out. The deoiled cake was composted with rice straw, four different animal dung (cow dung, buffalo dung, horse dung and goat dung) and hen droppings in different proportions followed by assessment, and comparison of biochemical characteristics among finished composts. Nutrient content in finished compost was within the desired level whereas metals such as copper, lead and nickel were much below the maximum allowable concentrations. Although a few finished material contained phorbol ester (0.12 mg/g), but it was far below the original level found in the deoiled cake. Such a study indicates that a huge volume of jatropha deoiled cake can be eliminated through composting.     

Chemical and biological changes during composting of different organic wastes and assessment of compost maturity

Changes in organic C, total N, C:N ratio, activities of cellulase, xylanase and protease, and microbial population were determined during composting of different organic wastes such as mixture of sugarcane trash and cattle dung, press mud, poultry waste and water hyacinth biomass. There were losses of N in poultry waste and water hyacinth with the effect an initial increase in C:N ratio was observed which decreased later on due to decomposition. The activities of cellulase, xylanase and protease were maximum between 30 and 60 days of composting in various wastes. Similar trend was observed with respect to mesophilic bacterial and fungal population. Various quality parameters like C:N ratio, water soluble C (WSC), CO(2) evolution and level of humic substances were compared after 90 day composting. There was statistically significant correlation between C:N ratio and CO(2) evolution, WSC and humic substances. Significant correlation between CO(2) evolved and level of humic substances was also observed. The study shows that no single parameter can be taken as an index of compost maturity. However, C:N ratio and CO(2) evolved from finished compost can be taken as the most reliable indices of compost maturity.     

Effect of fungal consortium and animal manure amendments on phosphorus fractions of paddy-straw compost

The study was conducted to reveal the type of phosphorus (P) fractions present in mature compost prepared by co-composting paddy straw (P.S) with cattle manure (CM), farm yard manure (FYM) and poultry manure (PM), each added separately as nitrogen (N) and P source. A consortium of phytate mineralizing fungi developed by including Aspergillus niger ITCC 6719, Aspergillus flavus ITCC 6720 and Trichoderma harzianum ITCC 6721 was applied for recovery of P from plant and animal residues. Chemical evaluation of compost after 4 months of aerobic decomposition revealed that inoculation improved the sodium bicarbonate-extractable P content of CM and FYM supplemented P.S compost by 32.3% and 23.5% respectively compared with their respective un-inoculated control. However, the peak values for water soluble-P fractions were recorded in CM–straw compost followed by PM–straw compost. Fungal inoculation also improved the agronomic quality of PM–straw compost as the latter had the highest total P content and lowest C:N and E4/E6 ratio of 18:1 and 5.36:1 respectively. The recovery of organic P from agricultural residue has the potential to reduce the application of synthetic P fertilizer. P-enriched organic manure can offer potential environment and economic benefits to farmers under sustainable agriculture.     

Accelerated coffee pulp composting

The effect of two abundant, easily available and very low-cost agro-industrial organic residues, i.e., filter cake from the sugar industry and poultry litter, on the composting stabilization time of coffee pulp and on the quality of the produced compost, was evaluated. Piles of one cubic meter were built and monitored within the facilities of a coffee processing plant in the Coatepec region of the State of Veracruz, Mexico. Manual aeration was carried out once a week. A longer thermophilic period (28 days) and a much lower C/N ratio (in the range of 6.9–9.1) were observed in the piles containing the amendments, as compared to the control pile containing only coffee pulp (14 days and a C/N ratio of 14.4, respectively). The maximum assimilation rate of the reducing sugars was 1.6 g kg-1 d-1 (from 7.5 to 5.3%) during the first two weeks when accelerators were present in the proportion of 20% filter cake plus 20% poultry litter, while they accumulated at a rate of 1.2 g kg-1 d-1 (from 7.4 to 9.13%) during the same period in the control pile. The best combination of amendments was 30% filter cake with 20% poultry litter, resulting in a final nitrogen content as high as 4.81%. The second best combination was 20% filter cake with 10% poultry litter, resulting in a compost which also contained a high level of total nitrogen (4.54%). It was concluded that the use of these two residues enhanced the composting process of coffee pulp, promoting a shorter stabilization period and yielding a higher quality of compost.     

Influence of straw types and nitrogen sources on mushroom composting emissions and compost productivity

The effects of different straw types and organic and inorganic nitrogen (N) sources on the chemical composition and odor concentration (OC) of mushroom composting emissions, compost parameters, and mushroom yield were examined using bench-scale and large-scale (windrows and aerated tunnels) composting systems. There were close correlations between the butanol or combined H₂S+dimethyl sulfide (DMS) concentration and OC of air samples taken from different composting ingredients (r=0.83 and 0.76–0.87, P<0.01, for log_e-transformed data). Differences in N availability, in terms of NH₃ and N losses during composting, were found between different N sources. Materials in which the N was less available (chipboard and digester wastes, cocoa shells, ammonium sulfate) produced lower mushroom yields than materials in which the N was more readily available (poultry manure, urea, brewers' grains, hop and molasses wastes, cocoa meal). Replacement of poultry manure with the other N sources at 50–100% or wheat straw with rape, bean, or linseed straw in aerated tunnel or windrow composts reduced the OC and emissions of odorous sulfur-containing compounds, but also reduced yield. Urea and cocoa meal may be suitable for “low odor” prewetting of straw, with addition of poultry manure immediately before aerated tunnel composting. Rape straw in compost reduces the formation of anaerobic zones and resulting odorous emissions, since it maintains its structure and porosity better than wheat straw. Journal of Industrial Microbiology & Biotechnology (2002) 29, 99–110 doi:10.1038/sj.jim.7000292 Received 08 January 2002/ Accepted in revised form 20 June 2002     

Composting of tannery effluent with cow manure and wheat straw

Wastewater from the leather industry in León (Guanajuato, México) is discharged into the Turbio river without treatment. Tannery wastewater contains utilizable nutrients, but also toxic organic compounds which might affect soil processes and plant growth, and pathogens, which might pose a threat to the local farming community. Tannery effluent was composted with cow manure and wheat straw for 90 days to reduce pathogens and toxic organic compounds and monitored. The compost was characterized by an electrolytic conductivity (EC) of 28.1 ms cm(-1), cation exchange capacity of 17.7 meq 100 g(-1), an absorbance at 645 nm of 0.0175, a respiration rate of 0.062 mg CO2-C kg(-1) compost-C day(-1), pH 8.5 and C:N ratio 7:1 with a germination index for cress (Lepidium sativum) of 48% after 90 days. Less than 10 faecal coliforms and no Salmonella sp., Shigella sp. or eggs of helminthes were detected in the compost while total coliforms decreased by log10 of 2. Total concentrations of lead (Pb) were 8.9 mgkg(-1) dry compost, chromium (Cr) 77 mg kg(-1) dry compost, cadmium (Cd) 0.4 mg kg(-1) dry compost, copper (Cu) 10.3 mg kg(-1) dry compost and sodium (Na) 14,377 mg kg(-1) dry compost. The compost characteristics indicated that it was mature, but the germination index for cress of less than 50% suggested possible remaining phytotoxic compounds. However, the large salt concentrations (especially Na), might have inhibited cress development and thus reduced the germination index. The large salt concentration might thus limit the use of this kind of compost.     

Effect of inoculating white-rot fungus during different phases on the compost maturity of agricultural wastes

The lignocellulolytic microorganism, Phanerochaete chrysosporium, was inoculated during different phases of agricultural wastes composting, and its effect on compost maturity was studied. In the three runs, the decrease in C/N ratio and increases in germination index and humification indices (humification ratio, humification index, percentage of humic acids and degree of polymerisation) were found. Furthermore, the different effects of inoculation during different phases on the compost maturity could be observed by using ANOVA. When inoculated during the second fermentation phase, P. chrysosporium induced significant changes on all parameters of compost maturity except C/N ratio, whereas it did not produce an obvious change on these parameters when inoculated during the first fermentation phase.     

Microbial indicators for sawdust and bark compost stability and humification processes

To what extent some microbial index ratios are suitable for use as early criteria for the level of compost stability during aerobic composting of coniferous sawdust and bark at mesophilic conditions was studied. Evolution of the specific respiration activity (CO₂-C/biomass C) and the ratios between some groups of microorganisms were followed as a function of composting time. The specific respiration activity was found to be an early and most reliable indicator of compost stability. The peroxidase and polyphenoloxidase enzyme activity during composting, as well as the composition of newly-formed humus substances were studied. The duration of composting increased the quality of newly-formed humus substances (C_h.a.:C_f.a ratio; Ca-complexed humic acid and resistance of organo-mineral complexes). The quality of humus substances could be used to assess compost stability. However, the results can be applied only under defined conditions.     

The single-batch bioconversion of wheat straw to ethanol employing the fungusTrichoderma viride and the yeastPachysolen tannophylus

We have developed and optimized a single-batch process for the production of ethanol from wheat straw employing the fungusTrichoderma viride and the yeastPachysolen tannophylus. T. viride andAspergillus niger were examined for their ability to produce fermentable sugars from cellulosic waste materials, e.g. different kinds of straw and wood waste.T. viride most efficiently saccharified delignified wheat straw within 3 days at 25–30°C with a yield of reducing sugars of 27 g from 50 g delignified wheat straw. The resulting wheat straw hydrolysates contained xylose and glucose in a 1:1.6 molar ratio. After heat inactivation of fungal activities the sugars were converted to ethanol by the oxygen-tolerant yeastP. tannophylus in the same batch. Under the optimized conditions developed (all weights are per liter) 70 g natural untreated wheat straw (100%) yielded 50 g delignified straw (71.4%), which was saccharified to 27 g reducing sugars (38.6%). Fermentation of the sugars yielded 11.8 g ethanol (16.9%) and followed the molar equation: 1 xylose + 1.6 glucose 5.3 ethanol + 5.6 CO₂.     

Evaluation of maturity and stability parameters of composts prepared from agro-industrial wastes

The objective of this study was to evaluate changes in physical, chemical and biological parameters to assess the maturity and stability of composts prepared from mixture of different farm and agro-industrial wastes over a period of 150 days. All the composts appeared granular, dark grey in color without foul odor and attained an ambient temperature at 120 days of composting indicating the stable nature of composts. Correlation analysis showed that the optimal values of the selected parameters for our experimental conditions are as follows: organic matter loss >42%, C:N ratio <15, water soluble organic carbon (C(w)):organic N (N(org)) ratio <0.55, humic acid (HA):fulvic acid (FA) ratio >1.9, humification index (HI) >30%, cation exchange capacity (CEC):total organic carbon (TOC) ratio >1.7 and germination index (GI) >70%. Compost enriched with sewage sludge, pressmud and poultry waste matured earlier compared to composts either enriched with distillery effluent or un-enriched.     

麦草栽培姬菇配方的数学模型研究

借助二次通用旋转组合设计法研究了麦草栽培姬菇配方的数学模型,以探讨利用麦草替代棉籽壳的新配方.试验结果得出了配料的取值范围及最佳栽培配方,即麦草79％,麸皮15％,玉米粉4％,过磷酸钙1％,黄豆饼粉1％.在实际生产中很有应用价值.     

Rhizoremediation of cadmium-contaminated soil associated with hydroxamate siderophores isolated from Cd-resistant plant growth–promoting Dietzia maris and Lysinibacillus strains

In search of multitrait plant growth–promoting (PGP) inoculants, we introduced two cadmium-resistant bacterial strains, C4 (PG), C5 (WB), and their consortium C6 (PG × WB) isolated from metal-contaminated industrial waste–fed canal near West Bengal. The test isolates were biochemically characterized and screened in vitro for siderophore production. The infrared spectra revealed the hydroxamate nature of the siderophore produced. Further in green house, siderophore-based seed inoculation with selected PGP isolates exhibited stimulatory effects on seed germination (up to 85.4%), chlorophyll index (22.9 spad unit), shoot and root length (70% and 62.7%), tiller numbers (38.82%), spikelet numbers (52.2%), straw yield (62.2%), grain yield (76.1%), total dry matter of root and shoot (55.56% and 64.4%, respectively), and grain yields (76.1%) of tested wheat cultivars. The 16S rRNA sequencing identified strain PG and WB as Dietzia maris and Lysinibacillus sp. strains. Furthermore, inoculation of C6 (consortium) in both cultivar UP-2565 and KS-227 showed maximum Cd sorption capacity in roots (38.3% and 67.1%) and shoots (68.4% and 67.5%), respectively. Both the strains and their consortium showed a great potential to increase the growth and yield of wheat cultivars, which can also be utilized for rhizoremediation process.     

Composting of olive leaves and pomace from a three-phase olive mill plant

The composting of olive leaves and olive pomace from a three-phase olive mill was tested as a method for solid waste reuse. The process was carried out using a compost windrow and mixing olive leaves and pomace at a ratio of 1:2. Compost was retained in the windrow for 60 days during which thermophilic temperatures developed for the first 40 days. The compost was then placed into a closed area to mature for another 60 days. The final product proved to be high quality amendment with C/N 27.1 and high nutrient concentrations (N, 1.79%; P, 0.17%; K, 4.97%; Na, 2.8%). Mature compost presented the highest germination index (198%) reported to date, as the germination index in the majority of previous studies is under 80%. Furthermore, tests revealed that addition of 31.5 tons of compost per ha, could increase lettuce yield by 145%.     

Transformation of14C labelled plant components in soil in relation to immobilization and remineralization of15N fertilizer

Summary Uniformly¹⁴C labelled glucose, cellulose and wheat straw and specifically¹⁴C labelled lignin component in corn stalks were aerobically incubated for 12 weeks in a chernozem soil alongwith¹⁵N labelled ammonium sulphate. Glucose was most readily decomposed, followed in order by cellulose, wheat straw and corn stalk lignins labelled at methoxyl-, side chain 2-and ring-C. More than 50% of¹⁴C applied as glucose, cellulose and wheat straw evolved as CO₂ during the first week. Lignin however, decomposed relatively slowly. A higher proportion of¹⁴C was transformed into microbial biomass whereas lignins contributed a little to this fraction.After 12 weeks of incubation nearly 60% of the lignin¹⁴C was found in humic compounds of which more than 70% was resistant to hydrolysis with 6N HCl. Maximum incorporation of¹⁵N in humic compounds was observed in cellulose amended soil. However, in this case more than 80% of the¹⁵N was in hydrolysable forms.Immobilization-remineralization of applied¹⁵N was most rapid in glucose treated soil and a complete immobilization followed by remineralization was observed after 3 days. The process was much slow in soil treated with cellulose, wheat straw or corn stalks. More than 70% of the newly immobilized N was in hydrolysable forms mainly reepresenting the microbial component.Serial hydrolysis of soil at different incubation intervals showed a greater proportion of 6N HCl hydrolysable¹⁴C and¹⁵N in fractions representing microbial material.¹⁴C from lignin carbons was relatively more uniformly distributed in different fractions as compared to glucose, cellulose and wheat straw where a major portion of¹⁴C was in easily hydrolysable fractions.     

Effect of inoculation with Penicillium expansum on the microbial community and maturity of compost

Compost prepared from wheat straw and cattle/chicken mature was inoculated with the lignocellulolytic fungus, Penicillium expansum. Compared to uninoculated compost, the inoculated compost exhibited a 150% higher germination index, more than 1.2 g kg(-1)-dw of changes in NH(4)(+)-N concentrations, a ca. 12.0% higher humus content and a lignocellulose degradation that proceeded 57.5% faster. Culture-based determinations of microbial populations demonstrated that aerobic heterotrophic bacteria and fungi were about 1-2 orders of magnitude higher in inoculated than in uninoculated compost. The number of ammonifying, ammonium-oxidizing, nitrite-oxidizing, denitrifying bacteria and cellulose-decomposing bacteria was 6.1-9.0 log(10) CFU g(-1)-dw, 1.2-4.3 log(10) MPN g(-1)-dw, 3.5-6.8 log(10) MPN g(-1)-dw, 3.58-4.34 log(10) MPN g(-1)-dw, 1.4-3.8 log(10)MPN g(-1)-dw, and 4.2-8.8 log(10) CFU g(-1)-dw higher in the compost inoculated with P. expansum.     

Effect of biodelignification of rice straw on humification and humus quality by Phanerochaete chrysosporium and Streptomyces badius

The effect of biodelignification of rice straw by two different ligninolytic organisms, Phanerochaete chrysosporium (white-rot fungus) and Streptomyces badius (actinomycetes), on humus quality was investigated during a 56-day incubation at 30 °C. Lignin degradation, the release of humic extract (HE), humic acid (HA) and fulvic acid (FA), E4/E6 ratio of HA, and humification index (HI, HA/FA) were measured during the incubation. Lignin was degraded by both organisms, but to different extents. Lignin was degraded to 41% and 31% by P. chrysosporium and S. badius, respectively. HE released by P. chrysosporium and S. badius were, respectively, 2.10 and 2.13 times larger than that in the control at the maximum values. A significant correlation between lignin degradation and humus-related parameters involving HA fraction showed that both organisms are converting lignin to humic substances.     

White-rot fungal conversion of wheat straw to energy rich cattle feed

In order to improve the digestibility and nutrient availability in rumen, wheat straw was subjected to solid state fermentation (SSF) with white-rot fungi (i.e. Pleurotus ostreatus and Trametes versicolor) and the fermented biomass (called myco-straw) was evaluated for biochemical, enzymatic and nutritional parameters. The fungal treatment after 30 days led to significant decrease (P < 0.05) in cell wall constituents viz, acid detergent fiber (ADF), neutral detergent fiber (NDF), hemicellulose, lignin and cellulose to the extent of 35.00, 38.88, 45.00, 37.48 and 37.86%, respectively in P. ostreatus fermented straw, while 30.04, 33.85, 39.90, 31.29 and 34.00%, respectively in T. versicolor fermented straw. However, maximum efficiency of fermentation in terms of low carbohydrate consumption per unit of lignin degradation, favoring cattle feed production was observed for P. ostreatus on the 10th day (17.12%) as compared with T. versicolor on the 30th day (16.91%). The myco-straw was found to contain significantly high (P < 0.05) crude protein (CP; 4.77% T. versicolor, 5.08% P. ostreatus) as compared to control straw (3.37%). Metabolizable energy (ME, MJ/kg DM), percent organic matter digestibility (OMD) and short chain fatty acids (SCFAs; mmol) production also increased considerably from control straw (4.40, 29.91 and 0.292) to a maximum up to P. ostreatus fermented straw (4.92, 33.39 and 0.376 on 20th day) and T. versicolor fermented straw (4.66, 31.74 and 0.334 on 10th day), respectively. Moreover, the myco-straw had lower organic carbon and was rich in nitrogen with lower C/N ratio as compared to control wheat straw. Results suggest that the fungal fermentation of wheat straw effectively improved CP content, OM digestibility, SCFAs production, ME value and simultaneously lowered the C/N ratio, thus showing potential for bioconversion of lignin rich wheat straw into high energy cattle feed.     

小麦秸秆水浸提液对五种植物化感作用的研究

该文研究了不同浓度的小麦秸秆水浸提液对徐州地区2种玉米(郑单958和农大108)和3种常见玉米田间杂草(马唐、稗草和反枝苋)种子萌发和幼苗生长的影响。结果表明:当小麦秸秆浸提液浓度分别大于75、50和25 g·L~-1时,马唐、稗草和反枝苋种子的萌发受到显著的抑制;当小麦秸秆浸提液浓度分别大于50和37.5 g·L~-1时,玉米郑单958和农大108种子的萌发受到显著的抑制;但当小麦秸秆浸提液浓度大于37.5 g·L~-1时,马唐、稗草和反枝苋幼苗根和芽的生长均受到明显的抑制;当小麦秸秆浸提液浓度小于75 g·L~-1时,玉米郑单958和农大108幼苗根与芽的生长受到明显的促进,且郑单958幼苗叶片中叶绿素的含量以及郑单958的POD酶活性均得到提高。该研究结果表明较高浓度的小麦秸秆浸提液(50 g·L~-1)会抑制杂草的生长,有利于玉米郑单958的生长,为小麦秸秆还田和玉米田杂草的生态防治提供了理论基础。