scholarly journals Evaluation of Microbial Loads and Physico-Chemicals of Cassava Mill Effluent Simulated Soil

Author(s):  
Bassey Etta Agbo ◽  
Daniel Offiong Etim ◽  
Alfred Young Itah ◽  
Akan A. Brooks

Evaluation of microbial loads and physico-chemicals of cassava mill effluent simulated soil was carried out using standard microbiological and biochemical techniques. This was to determine the effect of cassava mill effluent (CME) on rhizosphere microbial loads, physicochemical properties, nitrogenous salt and heavy metals. The results showed that CME effect on the physicochemical determinants (pH, Ca, Mg, K) and heavy metal determinant (Fe, Zn, Co, Ni, Pb and Mn) was concentration dependents. The nitrogenous salts (NO3, NH4+ and NO2) levels progressively increased with no significant differences (p>0.05 ANOVA). The microbial isolates were: Saccharomyces sp, Mucorindicus, Fusarium sp and Gliocladium sp for the fungal group. The bacterial group were Chromobacterium sp, Corynebacterium sp, Bacillus sp, Acinetobacter sp and Escherichia coli while the nitrogen-fixing bacterial group were Azotobacter sp., Azospirillum sp., Frankia sp., Bradyrhizobium sp., Hebaspirillum sp., Cyanobacteria (or blue green algae), Anabaena sp, Nostoc sp., Clostridium sp. and Rhizobium sp. There was no significant differences (p>0.05) in the rhizosphere microbial load across the concentration gradient at the CME-simulated plot phyto-remediated by Centrosema pubesscens and Calopogonium mucunoides. Agricultural wastes such as cassava mill effluent should be properly treated before discharging to the environment in other to prevent the loss of nitrogen-fixing bacteria and total heterotrophic bacterial genera that could be of immense importance to man.

Metabolites ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 168
Author(s):  
John I. Hendry ◽  
Hoang V. Dinh ◽  
Debolina Sarkar ◽  
Lin Wang ◽  
Anindita Bandyopadhyay ◽  
...  

Nitrogen fixing-cyanobacteria can significantly improve the economic feasibility of cyanobacterial production processes by eliminating the requirement for reduced nitrogen. Anabaena sp. ATCC 33047 is a marine, heterocyst forming, nitrogen fixing cyanobacteria with a very short doubling time of 3.8 h. We developed a comprehensive genome-scale metabolic (GSM) model, iAnC892, for this organism using annotations and content obtained from multiple databases. iAnC892 describes both the vegetative and heterocyst cell types found in the filaments of Anabaena sp. ATCC 33047. iAnC892 includes 953 unique reactions and accounts for the annotation of 892 genes. Comparison of iAnC892 reaction content with the GSM of Anabaena sp. PCC 7120 revealed that there are 109 reactions including uptake hydrogenase, pyruvate decarboxylase, and pyruvate-formate lyase unique to iAnC892. iAnC892 enabled the analysis of energy production pathways in the heterocyst by allowing the cell specific deactivation of light dependent electron transport chain and glucose-6-phosphate metabolizing pathways. The analysis revealed the importance of light dependent electron transport in generating ATP and NADPH at the required ratio for optimal N2 fixation. When used alongside the strain design algorithm, OptForce, iAnC892 recapitulated several of the experimentally successful genetic intervention strategies that over produced valerolactam and caprolactam precursors.


The International Biological Programme served as a focal point for studies on biological nitrogen fixation during the 1960s. The introduction of the acetylene reduction technique for measuring nitrogenase activity in the field led to estimates becoming available of the contribution of lichens, blue-green algae, nodulated non-legumes and bacterial-grass associations, as well as of legumes. Other studies carried out on the physiology and biochemistry of the process led to the eventual purification and characterization of the nitrogenase enzyme. These studies, collectively, provided the springboard for current work, so essential in view of the present energy crisis, on how to increase the use and efficiency of nitrogen-fixing plants, on the metabolic regulation of the nitrogenase enzyme and on the genetics of the nitrogen-fixing process, both in higher plants and in free-living micro-organisms.


2005 ◽  
Vol 33 (1) ◽  
pp. 157-158 ◽  
Author(s):  
L.C. Crossman

Rhizobium spp. are found in soil. They are both free-living and found symbiotically associated with the nodules of leguminous plants. Traditionally, studies have focused on the association of these organisms with plants in nitrogen-fixing nodules, since this is regarded as the most important role of these bacteria in the environment. Rhizobium sp. are known to possess several replicons. Some, like the Rhizobium etli symbiotic plasmid p42d and the plasmid pNGR234b of Rhizobium NGR234, have been sequenced and characterized. The plasmids from these organisms are the focus of this short review.


2003 ◽  
Vol 185 (23) ◽  
pp. 6995-7000 ◽  
Author(s):  
Ho-Sung Yoon ◽  
Martin H. Lee ◽  
Jin Xiong ◽  
James W. Golden

ABSTRACT The filamentous cyanobacterium Anabaena (Nostoc) sp. strain PCC 7120 responds to starvation for fixed nitrogen by producing a semiregular pattern of nitrogen-fixing cells called heterocysts. Overexpression of the hetY gene partially suppressed heterocyst formation, resulting in an abnormal heterocyst pattern. Inactivation of hetY increased the time required for heterocyst maturation and caused defects in heterocyst morphology. The 489-bp hetY gene (alr2300), which is adjacent to patS (asl2301), encodes a protein that belongs to a conserved family of bacterial hypothetical proteins that contain an ATP-binding motif.


2019 ◽  
Vol 71 (6) ◽  
pp. 2018-2027
Author(s):  
Shoko Mihara ◽  
Kazunori Sugiura ◽  
Keisuke Yoshida ◽  
Toru Hisabori

Abstract In the nitrogen-fixing cyanobacterium Anabaena sp. PCC 7120, glucose 6-phosphate dehydrogenase (G6PDH) plays an important role in producing the power for reducing nitrogenase under light conditions. Our previous study showed that thioredoxin suppresses G6PDH by reducing its activator protein OpcA, implying that G6PDH is inactivated under light conditions because thioredoxins are reduced by the photosynthetic electron transport system in cyanobacteria. To address how Anabaena sp. PCC 7120 maintains G6PDH activity even under light conditions when nitrogen fixation occurs, we investigated the redox regulation system in vegetative cells and specific nitrogen-fixing cells named heterocysts, individually. We found that thioredoxin target proteins were more oxidized in heterocysts than in vegetative cells under light conditions. Alterations in the redox regulation mechanism of heterocysts may affect the redox states of thioredoxin target proteins, including OpcA, so that G6PDH is activated in heterocysts even under light conditions.


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