In recent years, there has been a dynamic development of alternative energy sources and the use of plant biomass for the production of bioenergy is one of the possibilities of improving the energy mix. Therefore, it is worth reaching for new, less popular and perspective solutions, which certainly include sorghum, a drought-resistant plant with a high yielding potential and various applications in the bioeconomy. The aim of the research was to determine the amount of bioethanol obtained from the biomass of three sorghum varieties (Rona 1, Santos, Sucrosorgo 506) grown in the main and second crop for three years in the temperate climate typical of Central and Eastern Europe. The yields of sorghum cultivars grown as main and second crops, chemical components of sorghum biomass (cellulose, hemicellulose, lignin) and the amount of ethanol per a ton of dry matter of straw and ethanol yield per hectare were evaluated. The experiments and research carried out show, especially in the second year, that the Sucrosorgo 506 variety can be recommended for the cultivation of biomass and its use for the production of lignocellulosic ethanol is effective, both in main and second crop cultivation. The discussed results were confirmed by detailed statistical analysis, incl. principal component analysis (PCA) and cluster analysis. To sum up, the production of bioethanol from sorghum biomass is possible in temperate climate and it does not compete with the production of food due to the possibility of growing sorghum after rye.

In this study chemical and enzymatic treatment of hemp biomass were optimized to obtain maximum ethanol production. In the first stage, physical and chemical pretreatment of hemp biomass was carried out. It was found that the Tygra variety is susceptible to alkaline treatment at an optimum concentration of 2% NaOH. Next, the effect of NaOH on the value of reducing sugars and the chemical composition of the solid fraction before and after the treatment was determined. Hemp biomass before and after the chemical treatment was analysed by FTIR spectra and SEM. The effect of enzymatic hydrolysis, i.e., substrate content, temperature, time, pH and dose of enzyme by means of Response Surface Methodology on glucose content was determined. The highest glucose value was observed at 50 °C, in time process between 48 and 72 h, and the dose of enzyme was not less than 20 FPU·g⁻¹. After the optimization of enzymatic hydrolysis two processes of ethanol fermentation from hemp biomass, SHF and SSF, were carried out. In the SHF process a 40% higher concentration of ethanol was obtained (10.51 g/L). In conclusion, hemp biomass was found to be an interesting and promising source to be used for bioethanol production.

The problem of global warming is still a major issue, alongside shrinking oil reserves. A great alternative to fossil fuels is offered by biofuels, such as bioethanol from lignocellulosic plants. The sorghum biomass can be effectively used in many industrial directions. It is possible to use every part of this plant; the grain can be used for food production and straw can be used for energy purposes, i.e., for bioethanol. The aim of this study was to analyze the possibilities of bioethanol production from five varieties of sorghum biomass, which is a waste product of seed harvesting. The yields of sorghum cultivars in a three-year vegetation period; the amount of cellulose, hemicellulose, and lignin in the biomass of sorghum; and the amount of ethanol obtained per hectare were evaluated. It was observed that the highest average yield for all cultivars, except GK Emese, was found in the second year of the study. The bioethanol yield per hectare from this biomass was the highest for Sweet Caroline and was 9.48 m³∙ha⁻¹. In addition, significant differences were found in the content of lignin and hemicellulose for the varieties tested in all years of the study and for the content of cellulose in the first and third years. The discussed results were confirmed by detailed statistical analyses, including combined matrices of Pearson correlation coefficients (cr_p) varieties and cluster analysis. In summary, the usefulness of the biomass of the studied sorghum varieties for the production of bioethanol was demonstrated.

Currently, fossil fuels are used to produce fuels and electricity, which are finite sources and have a negative impact on the natural environment. An excellent alternative to these fuels is biofuels, such as bioethanol from waste forest biomass. Pine needles are one of the most important available forest biomass materials with s significant impact on local understory vegetation. Forest waste biomass, which is a rich source of lignocellulose, can be used in various ways, such as for the eco-economical production of bioethanol. The aim of this study was to analyze the possibilities of bioethanol production from pine needle biomass obtained from forest land following different soil preparations and logging residue management. The pine needle dry matter yield, chemical components of pine needle biomass (cellulose, hemicellulose, lignin), and the amount of ethanol yield per hectare were evaluated. The highest average yield pine needle equal to 6.17 Mg∙ha⁻¹ was observed. Bioethanol yield per hectare from this biomass was the highest for plowing with the LPZ-75 plow and was 1.08 m³∙ha⁻¹. The discussed results were confirmed by detailed statistical analysis. To sum up, the researched pine needle biomass turned out to be an interesting raw material with the potential for bioethanol production.

Due to the threat posed by the spread of invasive plant species, there is an urgent need to develop effective methods of eradicating and managing their biomass. The aim of the study was to examine selected invasive plants in terms of their use for energy purposes and to find out whether they can be a raw material for the production of second-generation biofuels. First, their chemical compositions were determined. The higher heating value (HHV) and lower heating value (LHV) were also calculated. High values of the higher heating value, ranging from 18.490 MJ∙kg⁻¹ to 19.900 MJ∙kg⁻¹, indicate the possibility of using the biomass of invasive plants for energy purposes (combustion). All investigated invasive plant species were also subjected to the process of obtaining ethanol. This included an alkaline pretreatment with 1% sodium hydroxide, followed by a simultaneous saccharification and fermentation (SSF) process. The highest ethanol yield per ha of plants was obtained at 2.6 m³∙ha⁻¹ for the Reynoutria × bohemica biomass. The remaining species showed an ethanol yield below 2 m³∙ha⁻¹. The conducted research allows for the conclusion that the studied invasive plants can be a promising raw material for the production of bioethanol.

In recent years, the cultivation of hemp for seed has been gaining significant importance. Intensive breeding work resulted in the registration of a new oilseed hemp variety with high seed yield called Henola. Hemp of this variety is characterized by a vegetation period shorter by about a month, almost twice shorter technical length of plants and significantly larger inflorescences than fibrous hemp of the standard variety (Białobrzeskie). This work analyzes the efficiency of the second-generation bioethanol production process derived from the processing of waste biomass remaining after deseeding the panicles of the Henola variety. The research material consisted of biomass samples obtained from three variants of the fertilization experiment carried out at the IWNiRZ Experimental Farm in Stary Sielec in temperate climate conditions. In order to find out about the properties of the raw material, the chemical composition of hemp straw was tested and the bioethanol yield per 1 ha of crops was determined. Henola oilseed hemp straw yield was the lowest (10.6 Mg∙ha⁻¹) in the case of the control and the highest (11.3 Mg∙ha⁻¹) with the use of complex phosphorus, potassium and nitrogen fertilization. The average content of cellulose in the analyzed samples was 35.5%, holocellulose 68%, and hemicellulose 32%. The amount of lignin, in turn, was independent of the type of fertilization. The lowest bioethanol content, in the amount 7.11 g∙L⁻¹, was found in case of hemp fertilized with nitrogen, phosphorus and potassium, and the highest content amounting to 9.93 g∙L⁻¹ – for hemp fertilized with phosphorus and potassium, for which the ethanol yield, converted into straw yield was 2.7 m³∙ha⁻¹. The conducted research covers both the identification of pro-environmental solutions in the economy for the management of waste biomass and the implementation of the RED II Directive on the promotion of energy from renewable sources.