**Author details**

*Applications of Biochar for Environmental Safety*

The tar yield decreases as a function of increasing temperature from 26.18% at 500°C to 6.38% at 900°C. H2O and CO2 influence significantly the tar homogeneous transformations at 700–900°C, while the tar reforming effect of 15 vol.% H2O is significantly higher than that of 29 vol.% CO2. H2O and CO2 have obvious effects on the transformation of PAHs. H2O and CO2 not only directly affect the tar transformation on biochar but also indirectly influence the reforming of tar through changing the structure of biochar catalyst. The formation of additional oxygencontaining functional groups is strengthened with the concentration of H2O and CO2 increasing. During tar heterogeneous reforming over biochar, the transformation of small aromatic ring systems (3–5 fused rings) to larger aromatic ring systems (≥6 fused rings) in the biochar structure is promoted by the increasing concentration of H2O and CO2. The activation by H2O/CO2 of biochar impacted the biochar surface's morphology and distribution of metal species. Activation/gasification under a CO2 in an Ar atmosphere produced more micropores, while adoption under a H2O in an Ar atmosphere favored the formation of mesopores. With the existence of gasification agents, especially for H2O, the simultaneous creation of pore structures is necessary to maintain biochar's catalytic activity during tar reforming. H2O/ CO2 also indirectly affects tar destruction by influencing the biochar structure and distribution of AAEM catalysts, while the reaction is occurring to ensure enough active sites on the biochar surface to maintain its catalytic activity. The activation and/or activity-maintaining effects of H2O/CO2 can notably enhance the in-situ reforming of both large and small aromatic ring systems present in biomass tar.

This work is supported by the National Natural Science Foundation of China (51906052), the National Postdoctoral Program for Innovative Talents of China (BX20180086), China Postdoctoral Science Foundation Funded Project (2018M641826), Heilongjiang Provincial Postdoctoral Science Foundation, Foundation of State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering (2019-KF-14), and Fundamental Research Funds for

the Central Universities (Grant no. HIT. NSRIF. 2020052).

The authors declare no conflict of interest.

**4. Conclusions**

**Acknowledgements**

**Conflict of interest**

**64**

Dongdong Feng\*, Yu Zhang, Yijun Zhao and Shaozeng Sun School of Energy Science and Engineering, Harbin Institute of Technology, Harbin, China

\*Address all correspondence to<EMAIL_ADDRESS>
© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


**Author details**

Akindayo A. Sowunmi Department of Zoology, Hydrobiology and Fisheries Unit, University of Ibadan, Ibadan, Nigeria

\*Address all correspondence to<EMAIL_ADDRESS>
© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


**3.1. Wild yeast**

During fermentation, yeast and LAB cells are submitted to several stress factors, such as: high osmotic pressure and hydrostatic pressure, high concentrations of ethanol, anaerobic atmos‐ phere, temperature, and nutrient limitation [98]. Such pressures promote the genetic adapta‐ tion of the individuals, leading to the survival of only the fittest cells. The increasing number of such alterations will lead to changes in the fermentation subproducts, some of which contribute to the organoleptic properties of the final products. Consequently, some of those subproducts may contribute to improve the beverages and, in this way, increasing the diversification of this industrial niche. Furthermore, the utilization of microorganisms isolated from traditional products, as *chicha* or *cachaça*, in the fermentation or maturation of new drinks production can lead to development of new promising products.

Recently, wild yeast isolates from *cachaça* fermentation vats in Brazil were innovatively evaluated in the production of beer [99]. First, in that study, 21 isolates belonging to the collection of the Laboratory of Cell and Molecular Biology /UFOP were surveyed for the production of aroma compounds in the beers. For that, compounds known for their influence in aroma and flavor, such as higher alcohols, esters, acetaldehyde, diacetyl, and ethanol, were analyzed by gas chromatography. After a careful analysis of each aromatic profile, two superior isolates were chosen (LBCM78 and LBCM45). In the same study, LBCM78 and LBCM45 were shown to be suitable to the production of ale and lager beers, respectively. The physicochemical composition of the produced beers were analyzed and compared to similar beers produced by commercial brewer yeast strains [99]. As a result, in the production of a wheat beer, the commercial strain WB-06 showed higher values of n-propanol than LBCM78. However, no significant differences were observed in the isobutanol and isoamyl alcohol levels. Similarly, the LBCM45 and the commercial strain W-34/70 were used to produce a lager beer, and the final products were analyzed as before. Between those two beers, the productions of isobutanol or isoamyl alcohol were similar. Moreover, no differences were observed in the ethyl acetate and diacetyl content of all the different beers produced by the four strains. As a final step of that study, beers were submitted to a sensorial evaluation by a group of trained tasters, from the Craft Brewers Association of Minas Gerais. The wild yeast showed a similar production of ethanol to the commercial strains (3.41–4.80% v/v), and the sensory analysis of the beers produced from LBCM45 and LBCM78 strains showed good acceptance in the evaluation panel [99]. These results suggest that yeast strains isolated from *cachaça* vats have a great potential for the production of new beers since a good production of volatile com‐ pounds and ethanol were observed.


**2. Ageing and the Alzheimer's disease**

The current major demographic phenomenon in Europe is ageing. The share of older people in the population is increasing, and the age distribution picture is changing to an oval shape, and it is tending to look like a block. The ageing trend may be explained by (i) the increased longevity of people, (ii) the declined fertility and (iii) the ageing of "baby boom" generations.

In Europe, as the cohort of baby boomers gets older, the wider stripes of the pyramid move up in direction of the top of the pyramid. Younger generations and their low fertility are reflected by their narrow stripes at the base of the age pyramid. As the time goes by, the top highest age group of the pyramid enlarges as an increasing large share of very old people who are living longer lives (**Figure 1**) [4].

So life expectancy has been increasing and people are living longer. These longer lives may be lived in a healthy status, but most likely the additional years of life are lived in unhealthy conditions, in particular, the last years of life. Among the health conditions, the most prevalent in older ages is dementia, which includes Alzheimer's disease. This health condition is not a consequence of the ageing natural process, but it has a high prevalence among the older group of people [5]. It generates high economic and social costs, and for this reason it may be considered as one of the great challenges of society nowadays [5].

**Figure 1.** *Population age pyramid in Europe.*

*The Burden of Informal Caregivers of Alzheimer's Patients: An Estimation to Portugal DOI: http://dx.doi.org/10.5772/intechopen.90673*

#### **Figure 2.**

*Standardised death rate due to Alzheimer's disease. Source: Based on Eurostat [hlth\_cd\_asdr2] [8].*

Dementia (and Alzheimer's disease) is a syndrome, chronic or progressive, characterised by an abnormal and fast decline in the ability of people to reason and think (the decline of the cognitive function). Although consciousness is not affected, the remaining capacities are strongly diminished such as memory, thinking, orientation, comprehension, calculation, learning, language and judgement. Additionally, there is a decline in the emotional control and social behaviour [1].

Life expectancy for an Alzheimer's patient, after his diagnosis, is about 10 years. There are three stages of progressive gravity of the disease: early (2–4 years), mild (2–10 years) and late (1–3 years or more) stages. In the early stage, illness goes unnoticed, and its signs include forgetfulness, losing oneself in familiar surroundings and losing track of time. As the illness progresses, at the mild stage, the signs become clear, and patients begin to forget recent events and people's names, forget where they are, have difficulty communicating with others, need help with personal care and start to show behavioural changes as wandering and repeat questioning. When the last stage is reached, Alzheimer's patients are inactive and dependent. Their memories are seriously damaged and physical signs are obvious.

The clinical dementia rating (CDR) is the clinical instrument that measures the severity of dementia, including Alzheimer's disease. This instrument evaluates six domains of cognitive and functional performance of patients, including memory, orientation, judgement and community affairs. This instrument scores the patients impairment in five levels so that medical intervention is more adequate and effective.

CDR is not a clinical diagnosis; it rather is a measurement scale that helps the diagnosis of Alzheimer's disease. In fact, there is no single test that provides a consistent diagnosis of Alzheimer's disease. The diagnosis is a process of careful evaluation done by a multidisciplinary team which may include neurologists, geriatricians, nurses, psychologists and psychiatrists [6].

In Western Europe, in 2016, it has been estimated that 4,499,078 disabilityadjusted life years (DALY) were attributed to Alzheimer's dementia disease [7]. Mortality associated to Alzheimer's disease has been increasing in Europe (**Figure 2**). Women die more than men, but the rate of increase has been identical for both genders. This trend is expected under the current conditions of longer lives and advance medical knowledge.

Currently, there are no medicines that prevent Alzheimer's disease or cure it, and so the numbers of patients and deaths will continue to grow, as well as the burden on the people suffering the disease, on the caregivers and on the health system as a whole.