No Abstract

Identifying the constraining factors of production and yield gap is very important. Therefore; this research was performed to identify the production constraining factors of local rice cultivars. All management practices from nursery preparation to harvesting stages for 100 paddy fields of local rice cultivars were recorded through field studies, in Sari, from 2015-2016. In the CPA, the actual and calculated potential yield were 4495 and 5703 kg/ha, respectively and the gap was 1221 kg/ha. The yield gap caused by number of top-dressing variables was 324 kg/ha, equal to 27% of the total yield gap. The yield gap related to previous year of legumes cultivation was 218 kg ha-1, equal to 18% of the total yield variation. Among the 10 variables entered in the CPA model, the effects of top-dress fertilizer application and its application frequency and foliar application were remarkable, which could compensate a significant part of the yield gap (444 kg/ha, 37% of total) in the farmers’ fields by managing these variables. According to boundary line analysis (BLA) finding, actual yield mean on the basis of optimal limit related to 12 variables under study was 5369 kg/ha, with 881 kg/ha yield gap . Mean relative yield and relative yield gap for 12 variables (transplanting date, seedling age, number of seedlings per hill, planting density, nitrogen and phosphorous per hectare, nitrogen before transplanting, harvesting date, lodging problem, pest problem, diseases problem and weeds problem) were 83.64 and 16.35 kg/ha, respectively. Based on the finding, it can be stated that the model precision is appropriate and can be applied for both estimation of the quantity of yield gap and determining the portion of each restricting yield variables.

Pyroliysis is a good method for conversion of biomass to hydrogen rich gases. This route will be a technology till the end of 2nd century. In this paper advantages and disadvantages of Pyroliysis and its position in the world is reported. Economical investigations show that over to the high potentional of biomass production in our country, the expenses of biomass conversion to hydrogen rich gas can be minimized using a technical program. Cost of pyroliysis with technical program will reduse from 3/60$/Kg H2 to 2 $/Kg H2 until 2015.

The production of renewable fuels and the gradual replacement of fossil fuels have been one of the main challenges of researchers in recent decades. Biodiesel is one of the fuels that is used by various sources and used in diesel engines. The production of biodiesel from third-generation sources has faced many challenges, especially in recent years. In this research, biodiesel was produced from microalgae oil in two wet and dry methods of native Dunaliella Sp. of Iran, and its properties were studied. The results showed that the wet method (direct method) has a higher yield than the dry method because the biodiesel is produced directly from moist biomass. So that the maximum extraction efficiency of the oil in the wet method was 17. 4% and in the dry method it was 10. 2%. The best extraction yield was achieved at 60 ◦, C and 30 minutes. The duration of oil extraction in the wet method due to the removal of the drying and desalting steps is considerably shorter than in the dry method. Therefore, the wet method has a high potential for biodiesel production. The microalgae Dunaliella SP. the fatty acid profile has 14 to 20 carbons and the main portion is composed of Palmitic acid (36. 62%) and Stearic acid.

The use of renewable sources of energies, such as biomass, is becoming increasingly important as countries realize that bioenergy present an approach to their international commitments to reduce greenhouse gas emissions. Biomass with higher thermal energy value and optimal composition is more desirable for the thermal conversion systems. In present investigation, properties of ten different types of wood biomass relevant were evaluated. Important characteristics of the biomass for energy generation were moisture and ash content, volatile matter, elemental composition (C, H, N, S, and O), and high and low heating values (HHV and LHV). The heating value has been determined based on experimental and computational methods using colorimeter bomb and elemental content, respectively. The results showed that eldarica pine biomass had the highest content of sulfur, which is undesirable environmental factor in the bioenergy system. Regarding to the fixed carbon to volatile matter ratio, Citrus sinensis var. thomson has the lowest ratio, so it is the best biomass for the gasification process. The highest and lowest heating values were determined for poplar pruning residues (group a) and apple tree pruniong (group b and c), respectively. The highest and lowest HHV and LHV were measured for P. deltoides and Malus spp., respectively.

Microalgae have garnered significant attention as a promising source for biodiesel production due to their rapid growth, high lipid content, and minimal resource requirements. This study delves into the forefront of microalgal biofuel research by investigating emerging co-cultivation strategies aimed at optimizing biomass production for biodiesel synthesis. Through a nuanced exploration of diverse microalgal strains, this work pioneers innovative co-cultivation techniques designed to enhance synergies between different species, thus maximizing overall productivity. Microalgae are excellent options for the production of biodiesel since they have high lipid content and grow quickly. Nonetheless, difficulties in maximizing lipid and biomass production have led the technological advancement microalgal productivity using photobioreactors, closed systems and monitoring and genetic Engineering The article delves into the impact of Co-cultivation on microalgal growth such as improved Biomass production, enhanced lipid content and quality and nutrient utilization and recycling.

Baker's yeast Saccharomyces Cerevisiae (S. cerevisiae), belonging to the Ascomycota yeast type and being facultatively anaerobic, plays a key role in ecology, fundamental and evolutionary biology, biotechnology and industrial fermentations, in particular, in the production of fermented food and beverages. Saccharomyces Cerevisiae (S. cerevisiae) grows on substrates with a high sugar content and is an important ingredient in flour bakery and confectionery products. In yeast, glucose metabolism is carried out by oxidation or fermentation, in the first case, this leads to cell growth, and in the second – to the formation of ethanol. A high concentration of glucose or a low concentration of oxygen in the nutrient medium stimulates the Crabtree effect, which inhibits cell growth and increases the formation of ethanol. The article reveals the fundamental and applied biology of baker's yeast Saccharomyces Cerevisiae and reveals the technological methods of enriching beet molasses with nutrients in order to increase the yield of biomass. It is shown that the successful commercial production of baking yeast Saccharomyces Cerevisiae is determined by biological (Saccharomyces Cerevisiae yeast strain with good breeding indicators; crop size, etc.) and technological (molasses quality: nature, composition, and concentration of substrate; cheap, suitable for cultivation carbon source; easily controlled cultivation process to obtain the most viable biomass, physico-chemical conditions of cultivation, primarily temperature, pH; cultivation period; development of the canning process, etc.) condıtıons. In industrial production, Saccharomyces Cerevisiae baker's yeast is obtained either from collection centres at the initial stages, or its own strains are isolated and cultivated, and subsequently, cultures are maintained, ensuring consistency of quality and productivity. The breeding characteristics of baker's yeast are: the ability to adapt to changing cultivation conditions, because the composition of molasses has high variability; the efficiency of respiratory metabolism during yeast production, which determines the yield of biomass; biomass production; cell growth rate; the ability to ferment; ability to quickly convert carbohydrates into CO2; ethanol production; dehydration; the volume of the final product, structure, colour (carbohydrates, amino acids); stress resistance to environmental conditions, in particular, to cold stress; shelf life (acids, glycerine). Today, as shown in the article, technological methods for enriching beet molasses with nutrients have different solutions. Molasses is enriched with cereals (cottonseed, cereal germs, legumes, peanut fodder cake), plant hormones, specific growth factors, animal products (milk, whey, animal waste), ammonium sulphate, malt (expensive), aqueous ammonia, ammonium salts. The enrichment of molasses with nutrients based on the use of cereals, glucose syrup obtained from corn, date syrup, whey, cassava, forestry, and agricultural waste has commercial potential, since these approaches do not require special processing requirements and provide low production costs (exception: forestry waste). In the technology of Saccharomyces Cerevisiae biomass production, a population of diploid cells is used, since compared with haploid cells they are genetically more stable, characterized by faster and more active metabolism, and larger sizes.